Preheat oven to 330°F (150°С). Grease baking pan with butter or line with parchment paper.
In a mixer bowl, put eggs, sugar, and honey.
Add almond flour and mix again.
In another bowl, mush the butter and mascarpone cheese together using a fork.
Add the mascarpone and butter to the egg-sugar mixture and mix again.
Add orange zest and vanilla to the batter. Mix well for the last time.
Pour the batter into baking pan.
Sprinkle with sliced almonds.
Bake in the preheated oven until golden, about 45 minutes. Allow the almond cake to cool before removing it from the pan. Sprinkle with powdered sugar before serving.