Baked Parmesan Veggie Casserole | Creamy Vegetable Side Dish

Ingredients

• 2 cups broccoli florets
• 2 cups cauliflower florets
• 1 cup baby carrots
• 6 Tbsp. butter, divided
• 1 small onion, chopped
• 1 garlic clove, minced
• 1/4 cup all-purpose flour
• 2 cups milk
• 1 large egg yolk, beaten
• 1 cup grated Parmesan cheese
• 1/2 tsp. salt
• 1/8 tsp. pepper
• 1/2 cup seasoned bread crumbs