Preheat your oven to 350°F (175°C) and grease a doughnut pan with non-stick spray.

In a large mixing bowl, whisk together the flour, granulated sugar, baking soda, baking powder, salt, and ground cinnamon until well combined.

In another bowl, mix the pureed strawberries, buttermilk, eggs, melted butter, and vanilla extract until smooth.

Pour the wet ingredients into the dry ingredients and gently fold until just combined. Be careful not to overmix.

Spoon the batter into the prepared doughnut pan, filling each cavity about 3/4 full.

Bake for 12-15 minutes or until a toothpick inserted into the center comes out clean.

Allow the doughnuts to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.

Once cooled, dust with powdered sugar before serving.