Cheesy Vegetable Tart

For the pastry: mix together the potato starch, cornflour, brown rice flour and sweet rice flour in a mixing bowl and whisk to combine.

Add the xanthan gum, guar gum and salt and stir well.

Add the frozen butter and using an electric whisk mix on the lowest speed, until the edges of the butter pieces have started to soften.

Pour in the water and mix until absorbed.

Turn out the mixture onto a large sheet of non-stick baking paper and knead it together with your hands, just enough to bring it together.

Place another sheet of baking paper on top and gently roll the dough out to a rough rectangle, taking care not to roll over the edges.

Fold the bottom third of the dough towards the middle, then fold the top third on top of it.

Rotate the dough one-quarter turn to your right (clockwise).

Roll out the dough gently as before, until smoother and more cohesive. Fold the bottom third up and overlap the top third over it.

Rotate the dough one-quarter turn to your right (clockwise).

Repeat the turning, rolling and folding process twice more.

Wrap the folded dough in cling film and chill for 2 hours.

Remove from the refrigerator and stand at room temperature for about 20 minutes.

Repeat the turning, rolling and folding process twice more. Wrap the dough in cling film and chill for a further 2 hours, then stand at room temperature for about 20 minutes before using.

Heat the oven to 200°C (180° fan) 400°F gas 6. Grease a baking tray and place in the oven.

Roll out the pastry and cut into 4 evenly-sized rectangles. Place on the hot baking tray and score a border 1cm|1/2" from the edges with a sharp knife. Lightly prick the middle area with a fork.

For the filling: Brush the pastry cases with beaten egg. Sprinkle the parmesan over the pastry bases. Lay the peppers, mushrooms and mozzarella on top and season with salt and pepper. Drizzle with a little oil.

Bake for about 15 minutes until the pastry is puffy and golden.