Preheat oven to 350 degrees Fahrenheit. Mix together flour, salt, baking soda, baking powder, and pumpkin pie spice—set aside.
Whisk together pumpkin, oil, vanilla, sugars, and eggs for 2 minutes until smooth. Add in dry ingredients until just incorporated—do not over mix. Pour into a greased 9” round pan.
Take the cold butter and either using knives or a pastry cutter cut cold butter into the flour until you have a crumbly texture with pea sized butter chunks in it. Then mix in sugar, salt, oats, and cinnamon. Sprinkle over top of cake batter. Bake for 37-42 minutes.
Cool cake and then prepare the glaze. Whisk together powdered sugar and milk, drizzle over top of cake. Slice and serve.
Notes
Different ways to cut the butter into your streusel. You can use a pastry cutter, two knives, or even a food processor. Just cut that cold butter into your flour until you’ve got a crumbly mixture before adding the rest of the streusel.
Storage and Freezing Tips. This cake is best sealed in an air tight container at room temperature and is best eaten within 3 days.You can freeze this cake. Wrap it tightly in two layers of plastic wrap and place it in an air tight container to prevent any freezer burn. Thaw completely before eating. It’s best if eaten within three months.
To replace the pumpkin pie spice in this recipe, use the following instead:
1 ⅛ teaspoons ground cinnamon
¾ teaspoon ground ginger
⅛ heaping teaspoon ground cloves
⅛ heaping teaspoon ground nutmeg
⅛ teaspoon all spice
You can substitute an 8x8-inch pan for the 9-inch circle cake pan