Sweet Potato Caramelised Onion Tart with Goats Cheese and Thyme – gluten free
There’s something effortlessly elegant about a savoury tart. Portable and self-contained, they make the perfect picnic food, starter, or light meal. Whether served hot or cold, their flavour and texture never disappoint.
For me, tarts are also a great way to reuse, repurpose, and reinvent leftovers. They save money, reduce waste, and always taste delicious.
This particular tart came together from a few on-the-edge ingredients — leftover roasted sweet potato, baby spinach that was just hanging on, thyme from the garden, and a small round of goats cheese waiting to be used. The result? A beautifully balanced tart that’s rich, creamy, and comforting with a touch of tang from the cheese.
The caramelised onions truly make this tart shine. They add a deep sweetness that complements the savoury filling. These onions are also wonderful served alongside sausages or layered into a steak sandwich. If you prefer a less sweet version, simply reduce the sugar or cook them more traditionally by browning and deglazing slowly — it’s time-consuming, but worth it.
The pastry is gluten-free and can be made ahead and frozen — either raw as a disk or already shaped in the tart tin. You can even bake the tart completely, cool it, and freeze it for later. When needed, just defrost and warm through in a moderate oven. I like to keep both a raw shell and a cooked tart in the freezer for easy meals.
Why You’ll Love This Recipe
-
Elegant yet effortless: Looks impressive, tastes gourmet, but is simple enough for a weeknight dinner.
-
Naturally gluten-free: A golden, buttery pastry made without gluten that still holds together beautifully.
-
Perfect for any occasion: Ideal for picnics, brunches, light lunches, or dinner parties — serve hot or cold.
-
A great way to use leftovers: Transform roast veggies and greens that are past their prime into something amazing.
-
Rich, balanced flavours: The sweetness of caramelised onions and roasted sweet potato pairs perfectly with tangy goats cheese and earthy thyme.
-
Make-ahead friendly: Both the pastry and the full tart can be frozen for quick, stress-free meals later.
-
Customisable: Swap sweet potato for pumpkin or goats cheese for feta — it’s endlessly adaptable.
This Sweet Potato, Caramelised Onion, Baby Spinach, Goats Cheese & Thyme Tart is everything you want in a savoury bake — rich, golden, flavour-packed, and effortlessly elegant. Whether you’re making it for a light lunch, picnic, or easy dinner, it’s guaranteed to impress without any fuss.
What I love most about this recipe is its versatility — it’s the kind of dish that makes leftovers feel brand new and ingredients on their last legs taste incredible again.
Sweet Potato Caramelised Onion Tart with Baby Spinach and Goats Cheese (Gluten-Free)
Servings: 4
Pastry (1 large or 4 small)
-
1 ½ cups Gluten-Free Plain Flour
-
1 tsp Xanthan Gum
-
2 tsp Apple Cider Vinegar
-
60 g Cold Butter
-
2 Egg Yolks (or 1 whole egg)
-
¼ cup Milk or Cold Water
Caramelised Onions
-
500 g Brown Onions
-
1 tbsp Olive Oil
-
¼ cup Apple Cider Vinegar
-
⅓ cup Brown Sugar
Filling
-
1 Medium Sweet Potato, roasted
-
20 g Baby Spinach
-
20 g Goats Cheese
-
4 Eggs
-
150 ml Cream
-
Salt and Pepper
-
7 Sprigs Fresh Thyme
Instructions
-
Caramelised Onions: Heat olive oil in a large non-stick pan over medium heat. Slice onions finely into half-moons and cook until golden and soft, about 10 minutes.
-
Add vinegar and brown sugar. Stir until bubbling, then reduce heat to low and cook for 30 minutes, stirring occasionally until the liquid evaporates and onions are sticky. Cool completely.
-
Pastry: In a food processor, combine flour, xanthan gum, and butter until fine breadcrumbs form. Add egg and vinegar, pulse briefly, then add milk/water and pulse until just combined.
-
Bring together to form a ball, wrap in plastic, and chill for 1 hour.
-
Preheat oven to 190°C. Roll pastry between two sheets of silicone paper and line a tart tin.
-
Line with paper, add baking beads, and bake for 10–15 minutes until lightly golden.
-
Filling: Whisk together eggs, cream, thyme leaves, salt, and pepper.
-
Spread a thin layer of caramelised onions in the pastry shell. Layer in sweet potato, spinach, and goats cheese.
-
Pour in the egg mixture and shake gently to settle.
-
Bake at 180°C for 30–40 minutes, or until the centre is just set.
-
Garnish with extra thyme and goats cheese. Serve warm or cold.
Notes
-
For a shorter, flakier pastry, add a little more butter and reduce liquid.
-
Xanthan Gum helps elasticity in gluten-free dough and is available at most supermarkets or online.
-
The vinegar in the pastry adds smoothness and helps prevent cracking.
-
Rolling pastry between two sheets of silicone paper makes it easier to handle.
Storage & Serving Suggestions
Store:
-
Allow the tart to cool completely before storing.
-
Cover tightly with plastic wrap or place in an airtight container and refrigerate for up to 3 days.
-
For longer storage, wrap individual slices or the whole tart in plastic wrap and foil, then freeze for up to 2 months.
Reheat:
-
Reheat slices in a moderate oven (170°C / 340°F) for about 10–15 minutes, or until warmed through.
-
Avoid microwaving if possible, as it can soften the pastry.
Serve:
-
Delicious served warm or cold — perfect for brunch, lunch, or a light dinner.
-
Pair with a fresh green salad, a drizzle of balsamic glaze, or a side of roasted vegetables for a complete meal.
-
Serve mini versions as canapés or picnic bites.
-
Garnish with extra fresh thyme or a crumble of goats cheese just before serving for a touch of freshness.
Make It Your Own
This tart is wonderfully versatile — you can mix and match ingredients based on what’s in season or what’s left in your fridge. Here are a few easy variations to try:
-
Swap the Veggies: Replace sweet potato with roasted pumpkin, caramelised beetroot, or zucchini ribbons for a new twist.
-
Change the Cheese: Try feta, ricotta, or blue cheese in place of goats cheese for different levels of creaminess and tang.
-
Add Protein: Turn this tart into a heartier meal by adding crumbled bacon, smoked salmon, or roasted chicken pieces.
-
Herb Variations: Swap thyme for rosemary, basil, or parsley — whatever you have on hand.
-
Dairy-Free Option: Substitute goats cheese and cream with plant-based alternatives like coconut cream and vegan cheese.
-
Mini Tarts: Make individual tartlets for picnics, lunchboxes, or entertaining — they freeze and reheat beautifully.
This is one of those recipes that welcomes creativity. Use what you have, experiment with flavours, and make it your own signature savoury tart.
FAQ?
Q. Can I make this tart ahead of time?
Yes! You can make the tart up to 2 days ahead and store it in the fridge. Reheat in a moderate oven (170°C / 340°F) for 10–15 minutes before serving.
Q. Can I freeze the tart?
Absolutely. Once baked and cooled, wrap tightly in plastic wrap and foil. Freeze for up to 2 months. Defrost overnight in the fridge and reheat in the oven until warmed through.
Q. Can I use store-bought pastry?
Yes — if you’re short on time, use a pre-made gluten-free shortcrust pastry. Just blind bake before filling as per the recipe instructions.
Q. What can I use instead of goats cheese?
You can easily substitute goats cheese with feta, ricotta, or even cream cheese for a milder flavour.
Q. Is this recipe suitable for vegetarians?
Yes, this tart is completely vegetarian-friendly as written — just make sure your cheese and pastry are vegetarian certified if needed.
Q. Can I make this tart dairy-free?
Definitely! Swap the butter for vegan butter, the cream for coconut cream, and the goats cheese for a plant-based alternative.
Q. What should I serve with it?
This tart pairs beautifully with a simple green salad, tomato chutney, or roasted veggies for a balanced meal.

Sweet Potato, Caramelised Onion, baby spinach, goats cheese and thyme tart (Gluten Free)
Ingredients
Pastry (1 large or 4 small)
- 1 1/2 cup Gf Plain Flour
- 1 tsp Xanthan Gum
- 2 tsp Apple Cider Vinegar
- 60 g Cold Butter
- 2 Egg Yolk or 1 Whole Egg
- 1/4 cup milk or cold water
Caramelised Onions
- 500 g Brown Onions
- 1 tbsp Olive Oil
- 1/4 cup Apple Cider Vinegar
- 1/3 cup Brown Sugar
Filling
- 1 Medium Sweet Potato roasted
- 20 g Baby Spinach
- 20 g Goats Cheese
- 4 Eggs
- 150 ml Cream
- Salt and Pepper
- 7 Sprigs fresh Thyme
Instructions
- For Caramelised Onions: Heat a large non stick frying pan over medium heat.
- Halve the onions from root to tip. Place cut side down and very finely slice from the shortest end. (to create half moon shapes).
- Heat olive oil in pan on medium heat and cook off the onions, stirring until starting to brown and caramelise, approx. 10minutes.
- Add the vinegar and brown sugar and stir until the sugar has dissolved and the mixture is bubbling. Reduce heat to medium low.
- Cook stiring occasionally until all liquid has evaporated and absorbed, approx. 30minutes.
- Allow to cool.
- For Pastry: Combine flour, Xanthan Gum and butter in a food processor and whiz until fine breadcrumbs.
- Add Egg and Vinegar and pulse until just combined.
- Add the water/milk and pulse until barely incorporated.
- Tip out and bring together to form a ball. Wrap in plastic and allow to rest in the fridge for 1 hour.
- Oven preheated to 190c.
- Roll out the pastry between 2 sheets of silicone paper until the correct size for the tart tin.
- Place in tart shell and press into the corners. Line with silicone paper and place baking beads or dried beans to cover (this is to stop it puffing up)
- Bake for 10-15 minutes until just cooked and pulling away from the sides of tin.
- For Filling: Preheat oven to 180C
- Combine Eggs and cream and the leaves of 3 sprigs of thyme and whisk to combine. Season with salt and pepper. (I use a pirex jug for this it’s easier to pour the egg mix out later on)
- Place the tart tin on a flat tray (incase of leakage)
- Put a thin layer of the onions in the base of the pastry shell.
- Pile the remaining ingredients into the tart tin. (I like to pile it beyond the rim and have a mix of the ingredients showing)
- Pour the egg mix in slowly. To help the egg mix settle gently shake the tin. Also pouring a few different positions also helps with coverage.
- When filled place the tart into the preheated oven for 30-40minutes or until the egg mix has just set in the middle.
- Garnish with fresh thyme sprigs and some more goats cheese.
- Serve hot or cold.
Notes
- If you prefer a shorter pastry (code for more flakey and rich) add more butter and reduce the amount of liquid.
- Rolling the pastry between 2 sheets of silicone paper works best, but feel free to use which ever method your comfortable with.
- Xanthan Gum is available from most major supermarkets, green grocers/deli, heath food shops and online.
- The vinegar helps to add a smoothness to the pastry and also helps with elasticity.
If You Loved This Tart…
If you enjoyed this Sweet Potato, Caramelised Onion & Goats Cheese Tart, here are a few more recipes you’ll adore:
Chorizo, Pumpkin, Zucchini Frittata w Artichoke Salad
Ricotta, Kale and Roast Pumpkin and Zucchini (GF) Lasagne
Pin the Recipe for later
Did you make this Recipe?
If you make this tart, I’d love to see it! Snap a photo, tag @thekrookedspoon on Instagram, and use #thekrookedspoon so I can share your delicious creation.