Brown your beef and sausage together, breaking apart as it cooks.
Slice bell pepper and onion into small slices, roast under Low heat broiler for about 15 min.
Slice mushrooms, grated cheese, and drain as much juice out of diced tomatoes as possible, pop them into a food processor and chop into finer pieces.
Using about half of the dough, roll out thinly. Flour surface lightly using flour or cornmeal.
TIP: If you roll the dough up around rolling pin, it is easier to move.
Spray bottom and sides of a tart pan. Place dough over pan and gently fit it into the pan bringing the dough all the way up the sides.
Pour enough pizza sauce to cover bottom of dough.
Start layering pizza, meat, roasted bell pepper and onion, mushrooms, and tomatoes.
Sprinkle with pepper flakes if desired, cover generously with cheese. Repeat process without using pizza sauce. (Meat, onion, bell pepper, mushrooms, tomatoes, cheese). Roll out the other half of dough, place on top of tart pan, using your rolling pin, roll around the top edges, this will cut your dough. Now tuck the dough down inside the pan.
Bake 425° for 30 min. Remove and add a layer of cheese on top of crust, return to oven and bake another 15 min. or till cheese is browning and melted.
Let rest for 15 min. Remove tart ring and cut. Enjoy the fruits of your labor.
NOTE: If you roll your dough out thin, you will have extra dough when your finished, use this to make a regular pizza, refrigerate dough if not using until later.