Preheat oven to 350F. Line a large half sheet baking tray with a silicone baking mat or parchment paper and set aside.
In a large mixing bowl, use a hand mixer or stand mixer cream together butter and sugars on medium speed until light and fluffy, about 2 minutes.
Add egg and vanilla, and beat on low until incorporated. Add flour, coffee grounds, baking soda, and salt and beat until just combined.
Reserve ¼ cup of the chocolate for the tops and set aside. Fold in the remaining chocolate chunks.
Use a medium cookie scoop to scoop out 2 tablespoons of cookie dough. Use your hands to roll it into a ball. Place the cookie balls onto the lined baking sheet, spaced at least 2 inches apart (you can fit about 6-8 on a large cookie sheet). If you don't care to have smooth edges, you can just drop the cookie dough onto the baking sheet without smoothing it into a ball.
Bake for 8-10 minutes, until edges just start to brown. Do not overbake. The cookies may not look done in the middle, but they will continue to cook as they are cooling.
Remove from oven and allow the cookies to cool in the baking sheet for 5 minutes, then carefully press in some the chocolate chunks into the top of the cookies, and transfer to a wire cooling rack to cool completely.
