Preheat your oven to 350°F (175°C). Grease a muffin tin or line it with paper liners.

In a large mixing bowl, combine the chopped pecans, brown sugar, and flour. Stir until everything is well mixed.

In another bowl, beat the eggs and mix them with the melted butter.

Add the egg and butter mixture to the bowl with the dry ingredients, stirring until just combined.

Spoon the batter into the muffin cups, filling each about two-thirds full.

Bake for 20-25 minutes, or until the muffins are golden brown and set in the center.

Allow the muffins to cool slightly in the pan before moving them to a wire rack to cool completely.