1 tablespoon butter, to grease ramekins
2 tablespoons extra-virgin olive oil
1/3 cup minced shallot (from about 2 small shallots)
8 ounces sliced mixed mushrooms (cremini, oyster or shiitake, stems removed before slicing)
2 tablespoons chopped fresh thyme
6 large eggs
3/4 cup whole milk
1/2 teaspoon kosher salt
1/2 teaspoon ground black pepper
1/2 cup grated mozzarella cheese
Preheat the oven to 400°F. In a medium saucepan, warm the olive oil over medium-high heat. Add the shallot and sauté until soft and translucent, about 3 minutes. Add the mushrooms and a pinch of salt and cook until softened and fragrant, about 5 minutes. Fold in the thyme.
Grease four 8-ounce ramekins with a little butter, or use cooking spray instead. Place ramekins on a baking sheet so they’ll be easier to move to and from the oven.
In a small mixing bowl, beat the eggs with the milk, salt, and pepper. Divide the mushroom mixture evenly between the ramekins. Add a generous pinch of grated cheese on top of each. Ladle egg mixture over the top, stopping just below the top lip of the ramekin.
Place baking sheet in the oven and cook for 20 to 25 minutes, or until the tops are golden and have puffed slightly. Enjoy warm; cover and refrigerate any leftovers for up to 3 days.