Sift the flour into a large bowl. Add butter, cheese, baking powder, and salt. Knead well until you have a smooth, pliable dough. Wrap in plastic and refrigerate for 30 minutes.

Combine tomato paste, onion, garlic, sugar, oregano, salt, and pepper in a medium-sized bowl.

Preheat oven to 400°F (200°C). Remove dough from refrigerator. Flour a work surface and roll out to medium thickness.

Using a cookie cutter or glass, cut circles in the dough, and place them on a Gefen Parchment Paper-lined baking sheet. Spread one tablespoon of sauce onto each circle. Sprinkle mozzarella cheese on top and place in oven. Bake for about 10 minutes, until cheese is melted and crust looks ready.