Preheat oven to 400ºF. Grease muffin cups or line with muffin liners.
Combine 1 1/2 cups flour, 3/4 cup sugar, salt, cocoa powder, flaxseed, maca, and baking powder.
Place vegetable oil into a 1 cup measuring cup; add the egg and enough milk to fill the cup. Mix in the instant coffee and stir well.
Add this to the flour mixture. Add in ¼ cup of nuts, mini chocolate chips, and vanilla.
Fill muffin cups right to the top, and sprinkle with turbinado sugar and remaining nuts.
Bake for 15-20 minutes in the preheated oven, or until done.