Preheat oven to 350 degrees. Lightly grease a 2-quart baking dish and set aside.
Heat olive oil in a medium skillet over medium-high heat. Add onions, bell peppers and 1/2 tsp salt and cook for 10 minutes, stirring frequently. Onions will begin to caramelize. Remove from heat and pour mixture into 2-quart baking dish.
In a large bowl, whisk together eggs, milk, salsa verde, a pinch of black pepper and the remaining 1/4 tsp of salt. Pour egg mixture into baking dish.
Top frittata with shredded cheese and bake for 45 minutes, making sure the middle of the frittata is fully cooked through.
Let cool for 5 minutes, serve with Salsa Verde Yogurt Sauce and enjoy!
For the salsa verde yogurt sauce
Add Chobani plain Greek yogurt, salsa verde and chopped cilantro into a blender. Blend until smooth.