Prepare a 12 cavity donut pan by spraying it with non-stick spray. Set aside.
Preheat oven to 350 F degrees.
In a bowl whisk together all purpose flour, salt, cinnamon powder, baking powder and baking soda.
Add to it granulated white sugar.
Whisk till all dry ingredients are well combined.
In another bowl, whisk together milk, vanilla extract and oil. Add the sour cream and mix.
Add the egg and mix till all wet ingredients are well combined.
Add the dry ingredients to wet in 2-3 parts. Don't dump the entire thing in one go.
Whisk till you get a smooth batter but do not over-mix. The batter will be thick.
Transfer batter to a piping/ziplock bag. Make a small cut and fill the donut pan with the batter till around 2/3rd full.
Bake at 350 F degrees for 9-10 minutes. Do not over-bake it. Take out of the oven and transfer on to a wire rack to cool completely.
Cookie butter glaze
To make the glaze take biscoff cookies spread, coconut oil and milk in a microwave safe bowl and microwave it on high for 20-30 seconds. Whisk till smooth.
Add vanilla extract, powdered sugar and mix till well combined and glaze is totally smooth. The glaze will thicken as it cools down.
Dip the donuts in the glaze once it has thickened a bit.
Garnish with crushed biscoff cookies and sprinkles (optional).