Preheat the oven to 200C/400F degrees
Make the dough, place all the dry ingredients in a bowl and blend well.
Add the oil and egg and stir until combined.
Add the boiling water, gradually until you have a dough. Firm up with your hands.
Roll out the dough by placing it on a piece of parchment paper, place another piece of parchment paper on top, then roll out. Cut out circles to cover the muffin tin spaces (I used a wine glass, but a large cookie cutter would do too).
Place the circles in a greased mini muffin tin and ensure that all the sides are covered with the dough.
Place about ¼ teaspoon of the Marinara sauce into each bomb.
Add Mozzarella cheese, pushing down until the bomb is full.
Gently squeeze the top edges of the dough together so that the dough forms little balls.
Sprinkle the tops with Parmesan cheese.
Bake for 20-25 minutes until the pastry is firm and golden.