Combine sugars and butter in a stand mixer with the paddle attachment. Cream together.
Add egg and vanilla and mix until just combined.
Add flour, salt, baking powder and coffee granules until just combined.
Add chocolate chips; mix until just combined.
Cover and chill for at least 2 hours, or up to 24 hours.
Preheat oven to 350. Line a baking sheet with parchment paper.
Using an ice cream scoop, scoop out dough and place on baking sheet, no more than 5 per baking sheet. The cookies will spread, keep them at least 2-3" away from each other.
Leave the dough in large balls, do not press them down. Sprinkle with flake salt if using.
Refrigerate rest of the dough while the first batch bakes.
Bake for 12 minutes, until edges are just golden.
Cool on the baking sheet for 7 minutes, then move to a cooling rack.