4tablespoonsunsalted butter, cut into small pieces
1cupmalted-milk powder
3ouncescream cheese, room temperature
1/4cupplus 2 tablespoons half-and-half
1teaspoonpure vanilla extract
Instructions
Preheat oven to 350 degrees F. Sift flour, cocoa powder, malted-milk powder, baking soda and salt.
Mix butter and sugar on medium speed until pale and fluffy. Mix in egg, vanilla and creme fraiche (or sour cream) and 3 tablespoons hot water. Reduce speed to low and mix in flour mixture.
Space tablespoon-size balls of dough 3.5 inches apart on parchment-lined baking sheets. Bake until flat and just firm. 10 to 12 minutes. Let cool on parchment on wire racks.
Melt chocolate and butter in a heatproof bowl set over a pan of simmering water, stirring. Let cool. Mix malted-milk powder and cream cheese on medium speed until smooth. Gradually mix in half-and-half, chocolate mixture and vanilla. Refrigerate, covered, until thick, about 30 mins. Mix on high speed until fluffy, about 3 minutes.
Assemble cookies: Spread a heaping tablespoon filling on the bottom of 1 cookie. Sandwich with another cookie. Repeat. Sandwiches can be refrigerated between layers of parchment in an air-tight container up to 3 days.