Spinach Quiche

Ingredients

• 1 frozen deep dish pie crust
• 1/2 cup chopped yellow onion
• 10 ounces frozen chopped spinach
• 4 large eggs
• 1/4 teaspoon crushed red pepper
• 1/4 teaspoon black pepper
• 1 1/4 cups half and half
• 1 tablespoon olive oil or butter
• 1 large egg yolk
• 1 cup shredded Gruyere cheese
• 2 garlic cloves
• 1 teaspoon kosher salt