In one bowl whisk flour, natural unsweetened cocoa, baking soda and fine salt; break up cocoa lumps.

In a separate bowl beat softened unsalted butter with brown and granulated sugar at medium speed for about 2–3 minutes until cohesive and slightly lighter.

Add the two eggs one at a time, then vanilla, mixing only until combined.

Add the dry mixture in two additions on low speed; finish folding by hand until no broad dry streaks remain.

Fold in 1 1/2 cups chocolate chips, reserving a spoonful from that measured amount if desired for visible tops.

Cover and refrigerate the dough at least 30 minutes; chill longer if the dough is unusually soft.

Preheat the oven to 350°F (175°C). Line light-colored baking sheets with parchment and scoop about 24 mounds, roughly 2 tablespoons or 38–40 g each, 2 inches apart.

Bake one sheet at a time for about 10–12 minutes; check for set edges and no wet raw center, adjusting for scoop size and oven.

Rest on the hot baking sheet about 8 minutes; then move to a wire rack until completely cool before storing.

Wash utensils and surfaces touched by raw flour or eggs; never taste raw cookie dough.