01 - Preheat oven to 350°F. Line a 12-cup muffin tin with paper liners or lightly grease with cooking spray.
02 - In a large bowl, whisk together mochiko, almond flour, baking powder, baking soda, and salt until well blended.
03 - In a small bowl, dissolve instant coffee granules (if using) in the cooled French roast coffee until fully integrated.
04 - In a medium bowl, whisk together sugar, eggs, milk, oil, melted butter, vanilla extract, and the prepared coffee mixture until smooth and uniform.
05 - Pour the wet ingredients into the dry ingredients. Gently fold together until just combined; do not overmix. Fold in chocolate chips or nuts if desired.
06 - Divide the batter evenly among the prepared muffin cups, filling each approximately 3/4 full.
07 - Bake for 20 to 22 minutes, or until the tops are set and a toothpick inserted into the center comes out clean.
08 - Let the muffins cool in the pan for 5 minutes, then transfer to a wire rack to cool completely before serving.