Step 1: Prepare Cinnamon Filling. Mix melted butter, brown sugar, and ground cinnamon in a medium bowl until combined. Transfer to a ziplock bag, seal tightly, and allow to thicken at room temperature for about 15 minutes.

Step 2: Make Pancake Batter. Whisk together the flour, baking powder, and salt in a large bowl. Gradually pour in the milk, vegetable oil, and beaten egg. Stir until just combined; it's okay if a few lumps remain.

Step 3: Make Glaze. In a microwave-safe bowl, combine cream cheese and melted butter. Heat in the microwave for about 30 seconds, then whisk until smooth. Gradually add powdered sugar and vanilla extract until creamy.

Step 4: Cook Pancakes. Preheat a non-stick skillet over low heat. Pour a small ladle of batter onto the skillet, about 4-5 inches in diameter. Pipe the cinnamon filling in a swirl on top of the batter. Cook for about 2-3 minutes until bubbles form, then flip and cook for an additional 2 minutes until golden brown.

Step 5: Serve. Stack pancakes on a plate, drizzling the creamy glaze over the top. Optionally sprinkle with powdered sugar, chopped nuts, or fresh berries. Serve warm.