Looks like pizza, tastes even better!

2 tablespoons olive oil
1 pound sweet Italian sausage (removed from casing)
1/2 yellow onion (peeled, small dice)
4 cloves garlic (peeled, minced)
1 cup San Marzano tomatoes (chopped)
2 large fresh bay leaves
Kosher salt and freshly ground black pepper (to taste)
2 tablespoons olive oil
7 cups water
Kosher salt (to taste)
2 cups instant polenta
1/2 cup mascarpone
1/2 cup Parmigiano Reggiano (freshly grated, plus more to garnish)
2 tablespoons unsalted butter
1 pound fresh mozzarella (grated)
1 cup fresh basil leaves (thinly sliced)

For the Sausage Ragu: In a Dutch oven over medium-high heat, warm the olive oil. Add the sausage to the pan, and cook until crispy and browned, about 5-6 minutes. Push the sausage to the side and add the onion and garlic, cooking until soft and translucent, about 2-3 minutes. Stir in the tomatoes. Season to taste with salt and pepper and bring to a simmer. Allow to cook until tomatoes have broken down, and sauce has reduced slightly, about 15-20 minutes. Re-season with salt and pepper if necessary.
For the Polenta: Brush an 18×13-inch baking sheet evenly with olive oil. Set aside.
In a large saucepan, add the water and season heavily with salt. Bring to a simmer.
Slowly add the polenta while whisking and reduce the heat. Cook over medium-low heat for 5 minutes, whisking frequently until smooth.
Remove from heat and whisk in the mascarpone, 1/2 cup of Parmigiano Reggiano, and butter. Season with salt to taste. Pour the polenta evenly into prepared baking sheet and place in the refrigerator, allowing to cool and harden for 1 hour.
To Assemble: Preheat the broiler.
Spoon the sausage ragu evenly over the hardened polenta. Evenly sprinkle the grated mozzarella on top of the ragu. Place the sheet tray in the oven and broil until the cheese has melted and the edges are crispy, about 5-7 minutes.
Remove from the oven and top with torn basil and freshly grated Parmigiano Reggiano. Slice into squares and serve!
Tip: Make the polenta the night before and allow it to harden in the refrigerator overnight to get ahead!