In a small bowl, add 2 tablespoons all-purpose flour, 1/8 teaspoon baking powder, the small pinch kosher salt, and 1 1/2 teaspoons sugar. Stir until the dry ingredients are evenly combined.

In a microwave-safe mug, add 1 1/2 teaspoons coconut oil, 1 1/2 teaspoons honey, and 2 tablespoons milk. If the coconut oil is solid, microwave the mug for about 10 seconds to melt it and help the honey dissolve.

Stir the wet mixture in the mug until the coconut oil and honey are fully incorporated into the milk.

Pour the dry flour mixture into the mug and stir until smooth, scraping the bowl to transfer all the dry ingredients.

Gently fold 1 tablespoon fresh blueberries into the batter so they are evenly distributed.

Microwave the mug on high for 50–60 seconds. Check the center; if it still looks wet, continue microwaving in additional 10-second bursts until the center is set.

Allow the muffin to cool in the mug for about 1 minute before enjoying.