Preheat the oven to 350°F and lightly grease a 10–11 inch quiche or tart pan.
Press the prepared crust evenly into the pan and set aside.
Bring a pot of salted water to a boil, add broccoli florets, and cook for about 3 minutes until tender-crisp. Drain well.
Heat olive oil in a skillet over medium heat and sauté the sliced red onion for 2–3 minutes until softened. Remove from heat.
In a medium bowl, whisk together eggs, sour cream, and shredded cheese until smooth. Season with salt, pepper, and Italian herbs.
Arrange all prepared vegetables evenly over the crust. Season lightly with salt and pepper.
Pour the egg mixture evenly over the vegetables.
Bake for 35–40 minutes, until the center is set and the top is lightly golden.
Let the quiche rest for about 10 minutes before slicing and serving.