Gently warm the milk, espresso powder, and unsweetened chocolate in a small bowl in a microwave on low until the chocolate is just melted. Do not overheat.

Let milk mixture cool. Meanwhile, place the softened butter and allulose in a large bowl and whip together with a hand mixer until light and fluffy.

Add the Keto Chow and vanilla extract and whip again until fully incorporated.

Add the cooled milk mixture and stir until completely mixed into the buttercream. If it is too stiff, add extra milk a tablespoon at a time until you reach your desired consistency.

Place in an airtight container and store in the fridge. Remove from the fridge the night before you plan to use it. If it is stiff, whip again for a few minutes before using, adding a tablespoon of extra milk at a time until you reach the desired consistency.