Zucchini Casserole: Addictively Delicious Cheesy Casserole

Ingredients

• 4 tablespoons butter, divided
• 1 small onion, chopped
• 2 garlic cloves, minced
• 6 small zucchini, chopped (about 7 cups)
• 3 cups cubed bread
• 2 large eggs, lightly beaten
• 1/4 cup heavy whipping cream
• 1 cup shredded cheddar cheese, divided
• 1 teaspoon salt
• 1/4 teaspoon pepper
• 1/4 cup shredded Parmesan cheese
• 1/2 cup panko bread crumbs