Make sure that the butter is cold, either straight from the fridge, or freeze it directly after cutting to chill for a few minutes.
Mix all ingredients together until it starts to clump together and is crumbly. You do not want to see any chunks of butter.
Gently break apart with your fingers, and chill in the fridge until you are ready to use. You want to avoid it getting soft before baking.
Preheat oven to 350F.
Cream butter with sugar until light and fluffy. Scrape down the bowl.
Add in eggs and vanilla. Scrape bowl.
Add in Farmer's Market Organic Sweet Potato Pie Mix and scrape bowl.
Sift dry ingredients together.
Alternate adding the dry in 3 parts with the milk in 2, ending with the dry. Don’t over mix. Only mix until incorporated, scraping between each addition.
Add to lined and greased pans.
Liberally coat top/s with streusel topping, gently pressing the topping into the cake batter.
Bake at 350 - time will vary based on oven and size of pan, but roughly 30-50 minutes. Make sure to rotate halfway. A toothpick should come out clean when it is done.