Preheat the oven to 350 degrees. Spray a 9 x 13 pan with cooking spray and set aside.
Cream the shortening, sugar, and brown sugar.
Add 2 eggs, flour, baking soda, baking powder, and 1 teaspoon cinnamon. Mix until combined.
Add the buttermilk. Mix until combined.
Pour batter into the 9 x 13 pan. Mix the topping ingredients together and sprinkle over the top.
Bake for 30-40 minutes, or until inserted toothpick comes out clean.
Notes
To make buttermilk, add 2 teaspoons of white vinegar to milk and let sit for about five minutes. The milk with thicken, just like buttermilk. If using the cake at a later time, refrigerate before baking. I also sometimes make this ahead and freeze before baking. Allow the cake to defrost in the refrigerator before baking. Some members of our family love this cake served with a pat of butter on top. Yum!
Recipe by The Gingham Apron at https://www.theginghamapron.com/overnight-coffee-cake-and-a-stained-recipe-card/