01 - Preheat oven to 375°F (190°C). Position the rack in the center of the oven.
02 - Heat olive oil in a large ovenproof skillet over medium heat. Add the asparagus, zucchini, and scallions. Sauté for 3 to 4 minutes until slightly tender but still vibrant in color.
03 - Stir in the baby spinach and thawed peas. Cook for 1 to 2 minutes until the spinach is fully wilted and the peas are warmed through.
04 - In a mixing bowl, whisk together the eggs, milk, salt, black pepper, and thyme leaves until well combined and slightly frothy.
05 - Spread the sautéed vegetables evenly across the bottom of the skillet. Pour the egg mixture over the vegetables and gently shake the skillet to distribute everything evenly.
06 - Scatter the crumbled goat cheese evenly over the surface of the egg mixture.
07 - Cook on the stovetop without stirring over low to medium heat for 3 to 4 minutes, just until the edges begin to set and pull away slightly from the sides of the pan.
08 - Transfer the skillet to the preheated oven. Bake for 12 to 15 minutes until the center is fully set and the top is lightly golden.
09 - Remove from the oven and let the frittata cool slightly before slicing into wedges. Serve warm or at room temperature.