Preheat oven to 400. Line your 12-cup muffin tin with baking cups.

For the crumb topping: combine all of the ingredients in a food processor and pulse until you have large coarse crumbs. (If you don't have a food processor, you can use a pastry cutter or a knife to cut through the butter until all of the mixture resembles large coarse crumbs.)

For the muffin batter: Using a stand or hand mixer, cream the butter and sugar together. Add the eggs one at a time and mix. Add the sour cream, vanilla, cinnamon, and salt. Mix until well combined. Reduce the speed to low and add the baking powder and flour. Mix until the batter is smooth. The batter will be thick.

Next, (you can mix the next 2 ingredients by hand if preferred) add the mini chocolate chips and mix on low. Add the dried cranberries (if using) and mix gently.

Place about 2 tablespoons of batter in each baking cup. Sprinkle 1 tablespoon of the crumb topping over each and follow with another 2 tablespoons or so of the batter. Lastly, top each muffin with the crumb mixture topping again.

Bake muffins for 12 minutes. Then, reduce the heat to 350 and bake for 15-17 more minutes or until the center springs back when touched.

Let the muffins cool in the pan for at least 10 minutes before taking them out.