Spiced Baked Apples: My Family's Crumble Topping Secret!

Ingredients

• 4 medium apples (such as Honeycrisp, Braeburn, or Granny Smith)
• 2 tablespoons unsalted butter, melted
• 1/4 cup apple cider or apple juice
• 1/2 cup rolled oats (not instant)
• 1/4 cup packed light brown sugar
• 1/4 cup chopped walnuts or pecans
• 2 tablespoons all-purpose flour
• 1 teaspoon ground cinnamon
• 1/4 teaspoon ground nutmeg
• Pinch of ground cloves
• 1/4 cup unsalted butter, cold and cut into small cubes
• 1/2 cup all-purpose flour
• 1/4 teaspoon ground cinnamon