Cheesy Polenta and Egg Casserole

1. Stage

Heat 1 tablespoon oil in a large saucepan or Dutch oven over medium heat. Add onion and cook, stirring, until softened, but not browned, 2 to 3 minutes. Add 4 cups water and bring to a boil. Gradually whisk cornmeal into boiling water. Add salt and cook over medium heat, whisking constantly until polenta bubbles, 1 to 2 minutes. Reduce heat to low and cook, whisking frequently, until very thick, 10 to 15 minutes. (Alternatively, once polenta comes to a boil, transfer it to top of a double boiler, cover, and place over barely simmering water for 25 minutes. This is convenient, because you don’t need to stir it as it cooks.)

2. Stage

Meanwhile, heat remaining 2 teaspoons oil in a large skillet over medium heat and add sausage. Cook, stirring and breaking sausage into small pieces with a spoon, until lightly browned and no longer pink, about 4 minutes. Drain if necessary and transfer to a cutting board; let cool. Finely chop when cool enough to handle.

3. Stage

Position rack in upper third of oven; preheat to 350 degrees F. Coat a 9-by-13-inch baking pan with cooking spray.

4. Stage

When polenta is done, stir in fontina (or mozzarella) and 1/4 cup Parmigiano-Reggiano. If polenta seems too stiff, add small amounts of water to thin it to a thick but not stiff consistency. Spread polenta in prepared pan.

5. Stage

Make six 2-inch-wide indentations in polenta with back of a tablespoon. Break eggs, 1 at a time, into a custard cup and slip 1 into each indentation. Scatter sausage on polenta and sprinkle remaining 1/4 cup Parmigiano-Reggiano evenly on top of eggs.

6. Stage

Bake casserole for 15 minutes. Then broil until egg whites are set, 2 to 4 minutes. Let stand for 5 minutes before serving.