1. In a small bowl, whisk together 1/2 cup melted butter, 3/4 cup brown sugar, and 1 tablespoon cinnamon until smooth. Pour into a sandwich-size zip-top bag and set aside on the counter to thicken.
2. In a microwave-safe bowl, heat 1/4 cup butter and 2 ounces cream cheese for 30–60 seconds until soft. Whisk in 3/4 cup sifted powdered sugar and 1/2 teaspoon vanilla until smooth. Set aside.
3. In a large bowl, whisk together 1 1/2 cups milk, 1 cup pumpkin puree, 2 eggs, 2 tablespoons oil, and 2 tablespoons apple cider vinegar.
4. In a separate bowl, whisk together 2 cups flour, 1 tablespoon baking powder, 1/2 teaspoon baking soda, 2 tablespoons pumpkin pie spice, 1/2 teaspoon salt, and 1 tablespoon brown sugar.
5. Add dry ingredients to wet ingredients and stir gently until just combined; do not overmix.
6. Check cinnamon filling; knead bag to re-incorporate if separated. The filling should be thick like toothpaste. Snip a small tip off the corner of the bag.
7. Preheat a large skillet or griddle to medium and spray with nonstick spray.
8. Scoop batter onto griddle (about 1/3 cup per pancake), spreading into even circles.
9. Reduce heat to medium-low. Pipe the cinnamon filling in a spiral on top of each pancake.
10. Cook for 3–4 minutes, until bubbles form and the underside is golden. Flip and cook 2–3 minutes more, until golden.
11. Wipe pan between batches as needed. Repeat with remaining batter and filling.
12. Serve pancakes warm, drizzled with cream cheese icing.