Preheat your oven to 425 degrees Fahrenheit. Line your muffin tin with paper liners in 6 spots. Fill the rest of the muffin holes with a small amount of water.
In a large bowl whisk together the flour, salt, and baking powder.
1 1/2 cups all purpose flour, 1/2 teaspoon salt, 2 teaspoons baking powder
Add in the apple sauce, oil, honey, milk, egg, and vanilla extract. Only stir until there are no streaks of flour left. The batter will be very thick.
1/4 cup apple sauce, 1 tablespoon olive oil, 1/4 cup honey, 1/3 cup milk, 1 large egg, 1 teaspoon vanilla extract
Gently fold in the frozen blueberries.
1 cup frozen blueberries
Fill 6 muffin cups all the way to the rim of the muffin liners.
Bake at 425 degrees Fahrenheit for 13 minutes, do not open your oven (see note 2). Reduce the heat to 325 degrees Fahrenheit and bake for 12 to 14 more minutes or until a tooth pick inserted in the center of a muffin comes out with just a few crumbs. (It is okay to check on your muffins about 6 minutes after you turn the temperature down to 325 degrees.)