- Slicer or Cutting board and 7″ rocking Santoku knife
- Large skillet
- Wooden spoon
- Measuring cup
- Measuring spoons
- Mixing bowls
- Ceramic baking dish
1 stick unsalted butter, plus additional for buttering the dish
4 pounds sweet onions, Walla Walla, or Vidalia onions, thinly sliced or cut into half moons
3 teaspoons salt, divided
3 tablespoons all-purpose flour
2 teaspoons baking powder
2 cups heavy cream
6 large eggs
3/4 cup freshly grated Parmesan cheese
Preheat the oven to 350F and butter a 9×13 ceramic or glass baking dish. Set aside.
In a stock pot, melt the stick of butter over medium heat. Add the onions and 2 teaspoons of salt and cook, stirring constantly, until the onions are softly caramelized and golden in color, about 40 minutes. Make sure not to burn the onions, so heat may need to be reduced to medium-low. Let the onions cool completely. This part can be done a day ahead.
In a small bowl, whisk the flour with the baking powder and 1 teaspoon of salt, set aside.
In a large bowl, beat the heavy cream with the eggs, then slowly incorporate the grated cheese.
Whisk in the dry ingredients with the wet ingredients until well combined. Then add the onions, gently folding into the mixture. Gently pour into the prepared baking dish and cook until the top is golden brown like cornbread, about 40-45 minutes. Make sure the soufflé is set, but has a little jiggle. Serve immediately.
The onions can be caramelized a day ahead.
You can also measure all the ingredients a day ahead, but it’s best to put the dish together the day of.
Gluten-free version: substitute Bob Red Mill’s 1 for 1. It takes a bit longer to cook, so you have to watch. You want it to be NOT jiggly in the middle, but not dry either, while slightly browning on top.
*This recipe was originally inspired by Sarah Simmons, Chef Owner of City Grit.
*This recipe was updated on November 20th, 2020 to reflect a change in the temperature of the heat in step one.
Keywords: thanksgiving side dish, holiday side dish, souffle dish