Special equipment: a 10-inch nonstick springform pan
For the pizza dough: Whisk together the lukewarm water, yeast and sugar in a small bowl. Let sit for 5 minutes, until the yeast begins to bubble and foam.
Add the flour and kosher salt to a stand mixer fitted with the dough hook and mix until just combined. With the mixer off, add the yeast mixture. Turn the mixer back on and knead, gradually increasing the speed from low to medium, until the flour and yeast are combined and the dough looks shaggy. Turn the mixer off again and add the melted butter. Mix, slowly increasing the speed to medium, until the dough holds together and the butter is completely incorporated, about 30 seconds. With the mixer on the lowest speed, knead the dough for 3 minutes. If the dough moves too high up the hook and is no longer being kneaded, turn the mixer off and push the dough back down.
Coat a large bowl with the olive oil. Remove the dough from the stand mixer, form into a ball and place in the greased bowl. (The dough will feel tacky when it comes out of the mixer but should come out in one piece. If necessary, knead additional flour into the dough, 1 tablespoon at a time, until the desired consistency is reached.) Cover with a towel and let rise in a warm place for 1 hour or until doubled in size.
For the marinara sauce: Heat the olive oil over medium heat in a medium saucepot. Add the onions and saute until softened, 2 minutes. Add the garlic and cook an additional 30 seconds, until fragrant but not browned. Stir in the tomato paste, oregano, crushed red pepper and salt; cook for 30 seconds. Pour in the stewed tomatoes, breaking up any large pieces. Bring the sauce to a boil, then reduce the heat to medium low and simmer for 10 minutes, stirring often. Remove from the heat and stir in the butter. Adjust the seasoning with salt to taste. Let cool. (Makes 1 1/4 cups.)
For the sausage pizza: Adjust an oven rack to the middle position and preheat the oven to 400 degrees F.
Heat the olive oil in a large skillet over medium-high heat. When hot, add the sweet Italian sausage and hot Italian sausage and cook until browned, breaking up the sausage into small pieces. Remove to a paper-towel-lined baking sheet to drain.
Combine the mozzarella and Asiago in a bowl and reserve in the refrigerator.
Place the proofed pizza dough on a lightly-floured work surface. Dust the top of the dough with flour and roll into a 14-inch round, about 1/4-inch thick. Roll the dough onto the rolling pin and transfer to a 10-inch nonstick springform pan. As evenly as possible, unroll the dough over the springform pan and guide the dough into the pan, pressing it evenly into the bottom and working it gently all the way into the edges. Next, lift the sides of the dough up and press against the sides of the pan, making sure the dough doesn't fold over itself at any point. The dough should come 2 inches up the sides of the pan.
Add half of the cheese to the bottom of the crust, top with half of the sausage and then cover the sausage with the marinara sauce. Add the remaining cheese, followed by the rest of the sausage. Fold the top of the pizza dough over so that it sits evenly on top of the filling.
Place the pizza on a baking sheet and bake for 20 minutes. Rotate, cover with foil, and bake an additional 20 minutes. Remove the pizza from the oven when the crust is a deep golden brown and the cheese is melted. Let rest for 15 minutes before removing the sides of the springform pan. Serve with torn basil scattered over the top.
To determine the right water temperature for activating yeast, hold your fingers under warm running water. If you feel no temperature, the water is about body temperature, 98 degrees F. Turn the hot water up slightly, just until it just begins to feel warm; this will be approximately 110 degrees F, perfect for activating yeast! When measuring flour, loosen the flour with a measuring cup before lightly scooping it into the cup. Level the flour with the back of a butter knife, sweeping the excess from the cup.