Preheat oven to 350 degrees.
Spray one 12-cup muffin tin with Pam or add paper liners to tin.
In a medium bowl, add all wet ingredients and lightly stir.
In a second medium bowl, add all dry ingredients and lightly stir.
Make a well in the flour mixture, and pour the wet ingredients into the flour mixture bowl.
Gently mix the muffin mix together by hand just until combined, careful not to over mix.*
With an ice cream scoop or large spoon, fill muffin cups about 3/4 cups full of muffin batter.
Prepare nut topping by mixing sugar, flour, chopped walnuts, cinnamon, nutmeg, and butter.
Quickly add 1 tablespoon or so of nut topping to the top of each muffin cup. **
Place muffin tin in oven and bake for 18-20 minutes when muffins are domed on the top and are a golden color.
Check for doneness in the center of muffins with a toothpick or knife.
Allow to cool for 5-10 minutes before gently easing each muffin from its cup or wrapper.
Cool completely on wire racks.