Apple and Cheddar Pierogy Casserole - Mrs. T's Pierogies

Ingredients

• 1 box Mrs. T’s® Mini Classic Cheddar Pierogies
• 1/4 cup unsalted butter, cut into cubes, plus melted unsalted butter, for brushing pierogies
• 1/4 cup apple juice
• 1 tablespoon cornstarch
• 4 large Honeycrisp apples, peeled and thinly sliced
• 3/4 cup packed brown sugar, divided
• 1 teaspoon ground cinnamon
• 1/4 teaspoon kosher salt
• 1/2 cup all-purpose flour
• 1/4 cup old-fashioned rolled oats
• 1 1/2 cups shredded cheddar cheese, divided