Ingredients
Method
Preheat oven to 350°F (175°C) and line baking sheets with parchment paper.
Cream butter and sugar until smooth, then add egg and vanilla.
In another bowl, whisk flour, cocoa powder, baking soda, and salt, then mix into wet ingredients.
Roll dough into small balls, flatten slightly, and place on baking sheet.
Bake for 8–10 minutes, then cool completely.
Mix filling ingredients until smooth and creamy.
Spread or pipe filling onto one cookie and sandwich with another.
Notes
Do not overbake cookies to keep them slightly soft. Chill dough if sticky. Adjust filling thickness by adding more or less milk. Store in airtight container for up to 4 days.
