In small bowl, mix powdered sugar & 1/4 C whipping cream with whisk; set icing aside.
In 2 qt saucepan, cook brown sugar, butter & cinnamon over medium heat, stirring often, until butter is melted & sugar is dissolved. Remove from heat; cover to keep warm.
In medium bowl, stir bisquick, milk & egg with fork or whisk until blended.
Preheat griddle or skillet over medium high heat. Grease griddle with vegetable oil if necessary (or spray with cooking spray before heating). For each pancake, pour about 2 Tbsp batter onto hot griddle. Cook until edges are dry & bubbles form on top. Turn & cook other sides until golden brown.
Serve pancakes stacked with warm cinnamon mixture between each pancake. Drizzle with icing in a swirl to make look like a cinnamon roll.