Preheat oven to 375°F (190°C) and line a 9×13-inch baking pan with parchment paper. In a bowl, combine almond flour, all-purpose flour, powdered sugar, and salt. Set aside.

1. Beat egg yolks with honey and vanilla until pale. Add melted butter, then fold in the dry ingredients. In a separate bowl, beat egg whites with granulated sugar until stiff peaks form. Gently fold egg whites into the yolk mixture. Spread batter in the pan and bake for 10-12 minutes. Let cool, then trim and cut into three even layers.
2. For the coffee syrup, combine brewed coffee and sugar in a saucepan, simmer until sugar dissolves, and stir in coffee liqueur. Set aside to cool.
3. For the coffee buttercream, beat butter with powdered sugar until fluffy. Add cooled brewed coffee, vanilla, and salt, then beat until smooth. Set aside.
4. For the ganache, heat heavy cream in a saucepan until simmering. Pour over chopped chocolate and stir until smooth, then add butter and let cool.
5. To assemble, place one cake layer on a platter, brush with coffee syrup, and spread with buttercream. Repeat with the second layer. For the third layer, pour ganache over the cake and spread evenly. Refrigerate for 2 hours.
6. Decorate with cocoa powder, chocolate shavings, or gold leaf. Slice and serve chilled.