Preheat oven to 350 degrees F. Grease mini or regular muffin cups generously. Grease them well or they will stick. In medium bowl, stir together brown sugar, flour and pecans. In a separate bowl, beat the butter and eggs together. Stir in dry ingredients just until combined.
Spoon batter into muffin cups about 2/3 full. Bake for 12-13 minutes for mini muffins or 15-17 minutes for regular size muffins. Run a knife around the edge of each muffin and pop it out.
Source: given to me by Tammy and adapted from Allrecipes