In a medium bowl, combine the streusel ingredients with your hands until it becomes crumbly. Set aside.
In a large mixing bowl, using either a stand mixer or an electric hand mixer, cream the butter and the sugar together. Add the eggs and sour cream and beat them in well. Add the vanilla, orange oil, orange zest, juice and combine.
Beat in the flour, baking powder, salt, and nutmeg and mix until combined. Scrape the bottom and sides of the bowl occasionally with a rubber spatula.
Gently fold in the chopped cranberries with a spatula.
Scoop or pour the muffin batter evenly into 12- paper lined muffin cups. Sprinkle streusel topping on the unbaked muffins.
Bake in a preheated 375 degree F oven for about 30 minutes. Or until a toothpick when inserted comes out clean. Let cool for 10-15 minutes before enjoying.