Melt the butter in a medium saucepan over low heat, then let it cool slightly. Blend the cooled butter with granulated sugar until well combined. Add the egg and vanilla extract, stirring until smooth.

Using a cookie scoop, portion out the dough and roll into uniform balls, about two inches in diameter. Transfer onto a parchment-lined baking sheet, flattening each slightly. Cover with plastic wrap and refrigerate for at least 30 minutes.

Preheat your oven to 180ºC (355ºF). Prepare another baking sheet with fresh parchment paper for baking.

Once the oven is heated, bake the cookies for 10-11 minutes, until the edges are set and the centers remain soft. Let them cool on the sheet for 3 minutes, then transfer to a wire rack.

Combine mascarpone, confectioners’ sugar, agave (or honey), and a pinch of matcha powder. Whip the mixture until stiff peaks form, about 3-5 minutes.

Once cookies have cooled, apply the mascarpone cream atop each cookie using a piping bag or dollop spoon. Lightly dust with additional matcha powder for presentation.