Preheat oven to 350.
Split tomatoes in half and scoop out the center/pulp into a bowl.
Place hollowed tomatoes into a baking pan and set aside.
Chop the tomato pulp/center.
Put the olive oil in a large skillet and add the meat and saute for about 4 minutes.
Add the diced onion, minced garlic, salt, black pepper, and red pepper flakes.
Cook and stir until meat is no longer pink.
Add bell peppers and diced tomato pulp and cook for 2 more minutes.
Remove from heat and allow to cool slightly (just enough so that it isn't hot enough to "cook" the egg when you add it in the next step)
Add beaten egg and bread crumbs mixing well.
Fill tomato halves with the filling mixture.
Place stuffed tomatoes in oven for 30-45 minutes until tomatoes are tender