Preheat oven to 350°F (175°C) and line an 8-inch square pan with parchment paper
In a bowl, mix almond flour, butter, cocoa powder, espresso powder, and 2 tbsp sugar. Press half the mixture into the pan as the crust
Bake crust for 12 minutes, then let cool slightly
In a separate bowl, combine gluten-free flour, baking powder, and 1/2 cup sugar. Whisk in butter, then add eggs. Pour over cooled crust
Bake brownie layer 18-20 minutes until toothpick comes out with moist crumbs
While baking, dissolve coffee granules in warm water and cool. Brush syrup onto hot brownie layer
In a stand mixer, whip egg yolks and powdered sugar until thick. Fold in Greek yogurt and citrus zest
Whip cream with vanilla extract until soft peaks form. Fold into yolk mixture
Spread this creamy layer over cooled brownie. Freeze for 1 hour before slicing into 12 pieces. Chill until ready to serve