In a small bowl, mix together flour, pecans, brown sugar, and nutmeg.

Use a pastry cutter or two forks to cut in 2 tablespoons butter until the mixture resembles coarse crumbs. Set aside.

Preheat oven to 375 F. Line 12 muffin cups with liners, or spray with baking spray.

In a large bowl, combine flour, brown sugar, baking powder, nutmeg, and salt. Set aside.

In another bowl, combine eggs, eggnog, and rum extract. Add egg mixture all at once to the flour mixture. Stir just until moistened (batter should be lumpy.)

Divide batter between 12 prepared muffin cups, filling each to almost full. Sprinkle streusel topping over muffin batter in cups.

Bake in a 375 degree F oven for 18 to 20 minutes or until golden and a wooden toothpick inserted in centers comes out clean.

Cool in muffin cups on a wire rack for 5 minutes, while you make the glaze:

Whisk together the butter, 1 tablespoon of eggnog, and nutmeg until smooth.

Add about half the powdered sugar, a little at a time.

Once half of the powdered sugar is incorporated, add remaining eggnog, whisking until smooth.

Add remaining powdered sugar, whisking until smooth. You want it VERY thick, but you can add extra water if you need.

Remove muffins from muffin cups; drizzle with glaze, and serve warm!