Heat oven to 375° F.
Drop a piece of butter in the bottom of each of 10 compartments of a muffin tin. Arrange the banana slices on top. Sprinkle the pecans and brown sugar over the bananas. Top each compartment with a biscuit. Bake until golden brown, 8 to 10 minutes. Remove from oven. Place a baking sheet on top of the tin while the buns are still hot. Carefully flip the tin over, tapping the bottom to release the buns. Transfer to a platter. Serve warm.