Melt the butter over medium heat in a medium saucepan. Stir continuously until it turns golden brown and releases a nutty aroma (about 4-5 minutes).

Remove from the heat and transfer it to a large, heat-safe mixing bowl. Set aside to cool for approximately 10 minutes.

Once the butter has cooled, add the sugar and beat until smooth and creamy.

Add the eggs, one at a time, mixing well after each addition.

Mix in the vanilla extract and instant coffee.

Combine the flour, baking soda, and salt in a small bowl. Then, slowly add the dry ingredients into the wet mixture until just combined.

Fold in the chopped dark chocolate.

Cover and refrigerate for at least 30 minutes (or up to 24 hours for enhanced flavor).

Preheat the oven to 350°F (175°C).

Portion 2-tablespoon-sized portions of chilled dough onto parchment-lined baking sheets. Be sure to leave about 2 inches of space between each cookie for spreading.

Bake for 10-12 minutes, until the edges are golden brown and the centers are slightly underbaked.

Cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely.

I like to sprinkle each cookie with a pinch of flaky sea salt while still warm.