Milk Chocolate Cookies with Malted Cream

Cookies:
¾ cup (1 ½ sticks/170g) unsalted butter, softened
½ cup (88g) light brown sugar, packed
½ cup (100g) granulated sugar
170g (6oz) milk chocolate, melted and cooled slightly
1 tablespoon pure vanilla extract
1 ¾ cups (245g) all-purpose flour
2 tablespoons unsweetened cocoa powder
1 teaspoon baking soda
1/8 teaspoon salt

Filling:
½ cup (113g/1 stick) unsalted butter, softened
½ cup chocolate malt powder, such as Ovaltine
1 teaspoon pure vanilla extract
1 ¾ cups (245g) confectioners' sugar, sifted

In a large bowl, using an electric mixer, beat the butter with the brown sugar and granulated sugar until creamy and smooth. Add the melted chocolate and vanilla and beat until smooth. In a small bowl, whisk the flour with the cocoa powder, baking soda and salt. Add the dry ingredients to the bowl and beat at low speed just until incorporated. Wrap the dough in plastic wrap and refrigerate for 30 minutes – in the meantime, preheat the oven to 180°C/350°F and line 2 baking sheets with parchment paper.
Roll the dough between 2 sheets of parchment paper to a 6mm (¼in) thickness and freeze for about 7 minutes. Using a 5cm (2in) round cookie cutter, stamp out as many rounds as possible and transfer to the baking sheets, 2.5cm (1in) apart. Gather the scraps and chill, with the cut-out rounds, for 10 minutes. Reroll the scraps and stamp out more rounds.
Bake the cookies, one sheet at a time (keep the other in the fridge) for about 10 minutes, until dry and set. Cool the cookies completely on the sheet over a wire rack.
Filling: in a medium bowl, using an electric mixer, beat the butter with the chocolate malt powder at medium speed until light, about 3 minutes – my mixture was a bit dry so I added 1 tablespoon sour cream to it (I would have used heavy cream if I had any). Add the vanilla and confectioners' sugar and beat until light and fluffy. Transfer the filling to a pastry bag fitted with a ½-inch plain tip. Arrange half of the cookies on a work surface, bottom side up, and pipe a 1-inch mound of filling onto each. Sandwich with the remaining cookies, pressing to spread the filling to the edges – I used a small cookie scoop instead of a pastry bag and placed rounded mounds of filling on the center of each cookie, topping with another cookie and pressing down gently to squish the filling.

Makes about 2 ½ dozen cookie sandwiches – I used a 4cm square cookie cutter and got 28 sandwich cookies