Gluten-Free Quinoa and Broccoli Casserole Recipe | Alton Brown

Ingredients

• 1 1/2 cups quinoa
• 3 cups chicken or vegetable stock
• 1 tablespoon kosher salt, divided
• 12 ounces broccoli florets, chopped
• 8 ounces button or cremini mushrooms, sliced
• 4 tablespoons unsalted butter, divided
• 1/2 large onion, diced
• 2 tablespoons dry mustard
• 1 1/2 teaspoons smoked paprika
• 1/2 teaspoon freshly ground black pepper
• 1/4 teaspoon cayenne pepper
• 1/4 teaspoon ground white pepper
• 3 cups half-and-half
• 1 large egg
• 16 ounces sharp Cheddar, grated
• 1/2 cup mayonnaise