01 - Preheat oven to 350°F. Line a 12-cup muffin tin with paper liners or grease lightly.
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.
04 - In a medium bowl, whisk sugar, eggs, milk, oil, melted butter, vanilla extract, and coffee mixture until smooth and emulsified.
05 - Pour wet ingredients into dry ingredients. Gently fold until just combined; avoid overmixing. Fold in chocolate chips or nuts if desired.
06 - Divide batter evenly among muffin cups, filling each about three-quarters full.
07 - Bake for 20 to 22 minutes until tops are set and a toothpick inserted into the center comes out clean.
08 - Let muffins cool in the pan for 5 minutes, then transfer to a wire rack to finish cooling.