Preheat your oven to 375°F (190°C).
Grease a muffin tin with cooking spray.
Unroll the crescent roll dough and separate it into triangles.
Press each triangle into the muffin cups, covering the bottom and sides.
Spoon about a tablespoon of pizza sauce into each crust.
Sprinkle a layer of shredded mozzarella cheese over the sauce.
Add pepperoni slices and diced bell pepper evenly on top.
Sprinkle Parmesan cheese and Italian seasoning over the pizzas.
Bake in the preheated oven for 12-15 minutes, or until golden brown.
Allow to cool for a few minutes before removing from the muffin tin.
Serve warm and enjoy your mini deep dish pizzas!