Preheat oven to 350 degrees F.

Grease mini muffin cups thoroughly but don't pile it on or your muffins will fry in the pan instead of bake. These have a tendency to stick. You can also grease and flour your pan or use Baker's Joy, if your pan is prone to stickiness. I used a non stick pan and sprayed with King Arthur Flour's Everbake and had no issues.

In a mixing bowl, beat softened butter and brown sugar until just combined. You don't want to whip any air into them, just make sure the sugar gets incorporated.

Add the eggs and vanilla and beat on lowest speed until combined.

Sprinkle the flour over the batter, add pecans and stir by hand until just combined.

Scoop batter into prepared muffin cups, about 2/3 full. You don't want to overfill the cup since these don't puff up very much. Too much batter will end up in a flat lip running over the cup.

Bake for 12-13 minutes for mini muffins and 15-17 minutes for regular size muffins.

Cool for about 2 minutes, then run a knife around the edge and remove. If they cool completely in the pan, you will likely have a tough time getting them out without destroying them. You just want them to have a couple of minutes to set up in the pan before removing them to a rack to finish cooling.

If you want to drizzle with chocolate, melt chocolate pieces and shortening or butter in the microwave stirring at 15 second increments until fully melted. Use a fork to drizzle, or spoon into a piping bag or zippered plastic bag with the corner cut off and drizzle over the muffins. If you want to fully cover each muffin with chocolate, you will have to double or triple the chocolate recipe.