FOR BATTER: Whisk together flour, baking powder and salt. Next Whisk in milk, oil and egg. Whisk only until batter is just moist... and if you have a few lumps, don't worry.
Next, mix butter, brown sugar and cinnamon in a separate bowl. Use a rubber spatula to scrape into a sealable plastic bag and set aside. (You're looking for it to have a texture similar to a paste.)
Heat butter and cream cheese in microwave until melted. Whisk to combine smooth, then whisk in powdered sugar and vanilla. Set aside
Coat a heavy fry pan with cooking spray and heat over med-low heat. Add apx 3/4 cup of the pancake batter to the pan, then squeeze out the cinnamon filling into a spiral shape by snipping the corner of the plastic bag.
Wait for small bubbles to appear on the pancakes, then flip. Cook 1-2 more minutes, until browned.