Preheat your oven to 350°F (175°C) and grease a doughnut pan.

In a large mixing bowl, whisk together the flour, granulated sugar, baking powder, salt, and cinnamon.

In another bowl, combine the milk, eggs, melted butter, and vanilla extract. Mix well.

Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix.

Gently fold in the sliced strawberries.

Spoon the batter into the prepared doughnut pan, filling each cavity about 2/3 full.

Bake for 10-12 minutes or until the doughnuts are golden brown and a toothpick inserted into the center comes out clean.

Allow the doughnuts to cool in the pan for 5 minutes, then transfer them to a wire rack to cool completely.

In a small bowl, whisk together the powdered sugar and 1 tablespoon of milk until smooth. Add more milk if needed to reach your desired glaze consistency.

Dip the cooled doughnuts into the glaze and let them set on the wire rack.