Deep Dish Pea and Vegetable Casserole

1 cup chopped cauliflower

1 cup sliced carrots

2 tablespoons butter

2 tablespoons all-purpose flour

1 cup milk

1 teaspoon white sugar

1 teaspoon salt

½ teaspoon ground black pepper

1 pound frozen peas, thawed

1 onion, chopped

1 cup green beans

½ cup chopped green bell pepper

1 tablespoon chopped garlic

2 cups shredded Cheddar cheese, divided

Place a steamer insert into a saucepan and fill with water to just below the bottom of the steamer. Bring water to a boil. Add cauliflower and carrots, cover, and steam until tender, 4 to 6 minutes. Drain and set aside.

Preheat oven to 350 degrees F (175 degrees C).

Melt 2 tablespoons butter in a large skillet over medium heat. Stir flour into butter to make a smooth mixture; cook for 1 minute. Stir milk, sugar, salt, and black pepper into the flour mixture; continue cooking and stirring until the sauce thickens, 2 to 3 minutes. Fold cauliflower, carrots, peas, onion, green beans, green bell pepper, and garlic into the sauce to coat. Mix 1 cup Cheddar cheese into the vegetable mixture. Transfer the mixture to a 2 1/2-quart casserole dish. Sprinkle remaining Cheddar cheese over the dish.

Bake in preheated oven until top is golden and cheese is bubbly, about 30 minute.