Preheat oven to 425°F.
Grease a quiche pan or skillet (9-inches wide, 2 inches deep) with Land O Lakes® Butter with Olive Oil and Sea Salt, then sprinkle all over with bread crumbs.
Place a large heavy skillet over medium heat, and the Land O Lakes® Butter with Olive Oil and Sea Salt. Add the sliced onion and sauté, stirring occasionally, until soft, about 10 minutes. Add the broccoli rabe and cook 6-8 minutes more until softened. Season with salt and pepper and transfer the vegetable mixture into the quiche dish, then evenly sprinkle cheese on top.
Whisk together the eggs, cream, milk, ½ teaspoon of salt and ¼ teaspoon pepper and pour over cheese.
Bake until the top is golden and custard is set in center, 25 to 30 minutes. Cool slightly before cutting into wedges and serve.
Optional: Serve with market greens tossed with lemon juice and olive oil over the top.