Preheat to 375 degrees. Prepare a baking sheet with foil. Melt butter in microwave for 30 seconds or in a small pan. Thinly slice red onion. Grease inside of pie pan with 2 tsp. olive oil. Measure and separate ½ cup of self rising flour and reserve. This separated flour will be used to prevent pizza dough from sticking to your work surface in the next step - it’s called bench flour. Place remaining flour in a mixing bowl with melted butter, all but 2 Tbsp. yogurt (one heaping spoonful), and a pinch of salt.

Mix with hands for 1-2 minutes, or until a loose crumbly ball is formed. (The dough will be fragmented until you turn it out and start kneading it.) Slightly coat a work surface with reserved bench flour. Turn dough onto dusted surface and knead for 5 minutes, folding the dough in half and pressing down with the heel of your hand. Dough may be slightly sticky, this is OK. If dough feels too wet, use a little of the reserved bench flour to dry it out. If dough seems too dry and crumbly, add reserved yogurt.

Using a rolling pin or wine bottle, roll dough into a 13” circle that's about ¼" thick, dusting underneath the dough with more bench flour as needed to prevent sticking. Carefully lift dough into oiled pie pan and press it into the corners snugly (avoid stretching dough, instead lifting excess dough from sides further down into the pan.) Trim any dough overhanging the pan.

Layer shredded mozzarella on dough. (Chicago deep-dish pizzas are "upside-down" and have cheese on the bottom and sauce on top.) Remove sausage from casing by cutting down lengthwise. Form an even layer of sausage on cheese. Arrange red onion (to taste- you may not need all the onion) over sausage. Top sliced onions with crushed tomatoes and season with a pinch of salt and pepper. Sprinkle top of pizza with dried oregano.

Place pizza pan on prepared baking sheet and bake for 35-40 minutes, or until internal temperature of the pizza reaches 165 degrees and crust is golden brown. Remove from oven and let cool for 5 minutes (this allows the pizza to hold together better for easier removal from the cake pan.)

If you're a pizza-blotter, grab your napkin and blot the top of the your pie, because this is some good sausage. Carefully remove the pizza from the cake pan with a spatula; you may have to bend or cut the the disposable pan with scissors to release the pizza. Garnish with grated Pecorino.