Preheat oven to 400 F. Grease or line a 12-cup muffin tin. If you grease the pan, be sure to grease the entire muffin tin as tops may rise out of the cup. Set aside.
In a large bowl, beat together butter and sugar until well-combined.
Mix in eggs and vanilla until combined.
Add milk and orange zest, and mix until incorporated.
Stir in 2 cups flour, baking powder, and salt.
In a small bowl, toss together cranberries and 1 tablespoon flour.
Fold in cranberries.
Divide batter among prepared muffin cups, and sprinkle tops with sugar.
Bake 5 minutes.
Without taking the muffins out, decrease oven temperature to 375F.
Continue baking for an additional 17-25 minutes, or until muffins are golden brown.
Let cool in pan for 5-10 minutes before removing.
Notes
Butter: I use salted butter in this recipe.
Milk: You can use any type of milk from skim to whole milk. You can also use nondairy milk if you prefer.
Sugar topping: The sugar topping is delicious but is optional.