Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper like the domestic goddess you are.
Make the flax egg and let it thicken while you pretend to clean.
In a bowl, whisk flour, cocoa, baking soda, and salt like you mean it.
Cream butter and sugars until fluffy—channel your inner pastry show contestant.
Add flax egg, vanilla, and milk. Beat well, then stir in the dry mix until smooth and luscious.
Scoop batter into 16 equal mounds on the baking sheet.
Bake for 12 minutes or until the edges are set but still soft. Let them cool while you try not to eat them.
For the filling, beat butter, espresso powder, sugar, vanilla, and plant milk until silky and dramatic.
Pipe or spoon the filling between two cookies. Press gently, but with confidence—like applying under-eye concealer.
Store in the fridge if you want firm centers. Or eat them warm because you’re a rebel.
