1.Preheat oven to 375 degrees, spray a nonstick muffin pan or grease. Or, use can use foil liners. Set aside.
2.In a medium to large mixing bowl, combine flour(s), sugar, salt, cornstarch and baking powder. Use a wire whisk to break up any clumps.
3.Measure out 3/4 cup milk, add in oil and vanilla extract. Pour into dry mixture. Gently mix just until batter is completely incorporated. Dig down to mix in all dry ingredients into wet. If the batter is very thick, you may want to add in the last 1/4 cup of milk. Gradually mix in. Batter should still be on the thick side.
4.Gently fold in blueberries that have been tossed with the 1 tablespoon of flour. Using a large cookie scoop, ice cream scoop or 1/3 measuring cup, fill the sprayed cups of the muffin pan.
5.Bake for about 15 to 20 minutes or until a toothpick comes out clean and the muffins gently spring back when lightly touched. Let cool in pan on a wire rack for about 20 minutes. Invert onto wire rack and let cool another 15 minutes. Enjoy!