Preheat oven to 350°F (175°C) and line a baking sheet with parchment like you mean business.
Stir flaxseed with water and let it chill for 5 minutes.
Cream vegan butter and both sugars until smooth and sassy.
Mix in flax egg, vanilla, and espresso powder.
Combine flour, baking soda, and salt in a separate bowl.
Add dry ingredients to wet. Stir until it forms a thick, moody dough.
Fold in those dreamy chocolate chips.
Scoop dough onto baking sheet, spacing them out like introverts at a party.
Bake for 12 minutes or until edges are golden and centers slightly underbaked.
Cool completely unless you're into meltdowns (frosting ones).
For frosting: beat vegan butter, powdered sugar, espresso, salt, and plant milk until spreadable and smooth.
Frost cooled cookies generously. Lick the spoon. We all do.