Afrittatais an easy way to turn eggs into a satisfying meal to serve hot or at room temp.
Heat a 10-inch ovenproof nonstick skillet over medium-high.
Add mushrooms and oil; cook, stirring often, until mushrooms start to brown, about 2 minutes.
Credit: Photography: Caitlin Bensel, Food Styling: Karen Rankin
Add shallots; cook, stirring occasionally, until starting to soften, about 4 minutes.
Add spinach in batches, stirring until wilted after each addition.
Reduce heat to medium.
Pour egg mixture into skillet, and tilt skillet to distribute egg evenly over vegetables.
Cook over medium until eggs around edges of skillet begin to set, 1 to 2 minutes.
Transfer skillet to preheated oven.
Bake until frittata is puffed and set, 10 to 12 minutes.
Serve hot, warm, or at room temperature.
