Preheat the oven to 375°F (190°C). Lightly grease muffin wells with nonstick spray.
In a small bowl, whisk together flour, baking powder, and salt.
In a medium bowl, whisk together sugar and oil. Add egg white, sour cream, vanilla, and lemon zest. Whisk until smooth. Stir in flour mixture until just combined (do not over-mix). Fold in blueberries.
Divide batter between prepared muffin cups, filling each 3/4 full. Optional: sprinkle the tops with a little extra sugar if desired.
Bake for about 16 to 22 minutes, until a toothpick inserted into the center comes out with just a few dry crumbs and when gently pressed, the top of the muffin springs back.
Cool in the pan for 5 minutes before transferring to a cooling rack.
Brew and prepare the coffee to your liking.
Mix the berries with the mint in a bowl.
Enjoy the muffins with berries and coffee.