Mix all dry ingredients together; ground almonds, coconut flour, baking powder and salt.
Mix in butter with hands to dry ingredients.
Mix in most of the egg, saving 1-2 tsps for glazing the pastry before baking.
Place in fridge to firm up.
Filling to Roast
Preheat oven to 160°C.
Slice all vegetables; aubergine, courgette, mushrooms, red onion, cherry tomatoes and garlic (including garlic for sauce).
Place in ovenproof dish and drizzle with extra virgin olive oil, salt and pepper and roast for 30-40 minutes, turning half way through.
Sauce
Blend tinned tomatoes, sundried tomatoes and cooked garlic to form sauce.
Combine
Preheat oven to 180°C.
Using a rolling pin and two pieces of greaseproof paper to roll the pastry out to desired shape. Do this by sandwiching the pastry between the two pieces of greaseproof paper to avoid the rolling pin touching and sticking to the pastry.
Arrange roasted vegetables to centre of pastry. Add sauce and other fillings: olives and your choice of cheese.
To form galette use the greaseproof paper to fold the edges towards the centre and shape with your hands.
Brush the remaining egg over the visible pastry.
Bake at 180°C for 20 minutes until the pastry looks golden.