1. Preheat oven to 375°F. Spray standard muffin tin with non-stick pan spray or use muffin liners.
2. Sift flour, instant coffee granules, baking powder, baking soda, and salt into large bowl; set aside.
3. In a medium bowl, whisk sugar with eggs until light, about 30 seconds. Whisk in bananas, milk, espresso or coffee, vanilla until combined. Stir in oats and cinnamon.
4. Whisk wet mixture into dry mixture until just combined, do not overtax. Stir in chocolate chunks.
5. Evenly divide batter between muffin cups.
6. Bake until set, 22 to 24 minutes or until the muffins begin to turn golden brown and toothpick inserted into the center comes out clean. Let muffins cool in pan 15 minutes,
then remove muffins from tin and place on wire rack to cool.
Store them in an airtight container at room temperature for up to 5 days.