Preheat your oven to 350° F. Spray donut pans with nonstick spray and set aside.
In a small bowl, mix together the flour, brown sugar, sugar, and cinnamon. Pour the cooled butter onto the dry ingredients and use a fork to mix until the flour is absorbed and a crumb starts to form. Don't overmix or you will turn the crumb into a mushy consistency. Put in the fridge and continue onto the batter.
½ cup + 2 tbsp all-purpose flour, ¼ cup brown sugar, 2 tbsp granulated sugar, ½ tsp cinnamon, 3 tbsp unsalted butter
In a large bowl, combine the flour, baking powder, baking soda, salt, and cinnamon. Set aside.
1 cup + 2 tbsp all-purpose flour, 1 tsp baking powder, ¼ tsp baking soda , ½ tsp salt, ½ tsp cinnamon
In a separate bowl, whisk together the brown sugar, egg, milk, yogurt, melted butter, and vanilla. Pour the wet ingredients into the dry ingredients and mix until just combined, being sure to not over mix.
¼ cup light brown sugar, 1 large egg, ¼ cup milk, ¼ cup plain greek yogurt, 3 tbsp unsalted butter, 1½ tsp vanilla extract
Spoon the batter into the donut pan cups. I like using a ziploc baggie to do this- piping the batter into each donut cup, filling about halfway.
Take your crumb topping and sprinkle over top of the donuts until each is covered. Gently press the crumbs into the donut batter.
Bake for 10-12 minutes, or until edges are set and top is lightly browned. Allow to cool in the pan for about 3-5 minutes and then transfer to a wire cooling rack. After they have cooled, dust with powdered sugar before enjoying! powdered sugar