In a large bowl, sift the flour, baking soda, baking powder, coffee and salt. Set aside.<br></br>
In a mixing bowl, beat the butter and sugars till light and fluffy, about 30 seconds.<br></br>
Add the egg yolk. Slice the vanilla bean down the middle vertically, then use a sharp knife to scrape it out, and add to the mixing bowl. Beat well.<br></br>
Fold in the flour mixture. The dough will be thick but sticky. Fold in the chocolate chips.<br></br>
If you're working in a warm kitchen, chill the dough for 10 minutes.<br></br>
Preheat the oven to 180 C and roll the dough into 8 equal rounds. Place at least an inch apart on a baking tray.<br></br>
Bake for 8 to 10 minutes, rotating the tray halfway, until the cookies are lightly browned on the edges. They will look soft and puffy, but don't over-bake.<br></br>
Press a few chocolate chips on top of the hot cookies and sprinkle on the sea salt. Let cool for 10 minutes on a wire rack so that they firm up and darken. Dig in!