In a medium bowl, whisk together eggs, milk (or cream), salt, and pepper until well combined. Set aside.
Heat olive oil in a 10-inch oven-safe skillet over medium heat. Add asparagus and cook 4-5 minutes, stirring occasionally, until just tender but still bright green.
Add spinach and peas. Cook 2-3 minutes, stirring occasionally, until spinach wilts and peas are warmed through.
Spread vegetables evenly across the skillet. Pour egg mixture over vegetables. Gently stir once to distribute, then let cook undisturbed on stovetop 2-3 minutes until edges begin to set.
Sprinkle crumbled goat cheese and chopped herbs evenly over top.
Transfer skillet to oven. Bake 10-12 minutes until center is set (no longer jiggly) and top is lightly golden.
Remove from oven and let rest 5 minutes before slicing. Serve warm or at room temperature.
Notes
Use a well-seasoned cast iron or nonstick oven-safe skillet—frittata will stick to stainless steel
Don't overcook asparagus in step 3—it continues cooking in the oven
Let frittata rest before slicing for cleaner cuts
Check doneness by gently shaking pan—center should be set, not jiggly
Wrap skillet handle with towel after removing from oven (it's hot!)
Easy variations:
Swap asparagus for zucchini, bell peppers, or broccoli
Use feta, ricotta, or cheddar instead of goat cheese