Preheat your oven to 220C fan assisted)/425*F
Make the flax egg by mixing the flaxseed with 3 tbsp hot water. Leave for 10 minutes to form.
Mix the flour, ground almonds, salt, and baking powder in a large bowl.
Add in the flax egg, olive oil, and water. Knead until you have a dough that holds together but is not too sticky. Add more water as needed.
Make the filling by sautéing the onion for 5 minutes on a medium/low heat. Add the garlic and chickpeas and continue cooking for another minute. Pour in the chopped tomatoes and add the tomato puree, balsamic vinegar, pesto, black pepper, chilli flakes, and crumble in the vegetable stock or mix it with a couple of tablespoons of hot water to help it dissolve first. Mix everything and cook until the mixture thickens.
Assemble: Divide the dough into 2 or 4 balls. Roll out on a floured surface into a circle about a ¼" thick. Transfer onto a baking tray covered with parchment paper. Spoon some of the mixture onto one half of the dough and then fold the other half on top. Seal the edges by pressing them down with the back of a fork and prick a few holes on top of the calzone. Bake for 15-20 minutes or until the top turns golden brown. Decorate with a drizzle of sriracha and fresh basil. Enjoy on the side of sweet potato fries and steamed broccoli.
