Preheat your oven to 350°F (175°C). Lightly butter a tart pan and set it aside. Yes, we’re starting with the boring but crucial preheat. Do it now, trust me.
Make the crust. In a bowl, mix almond flour, all-purpose flour, sugar, and salt. Cut in the butter with a fork or pastry blender until the mixture looks like wet sand. It should cling together when you pinch it.
Bind the dough. Beat the egg with vanilla and honey, then fold into the flour mixture until a shaggy dough forms. If it’s too crumbly, add a tiny splash of water; if it’s too sticky, chill it for 10 minutes. Pat it into a disk.
Roll and press. Roll the dough between parchment sheets until it’s about 1/8 inch thick. Transfer to the tart pan, press evenly along the bottom and up the sides. Trim the edges for a clean look.
Blind bake the crust. Prick the bottom with a fork to prevent puffing. Bake 12–14 minutes until lightly golden. Remove from oven and let cool a bit.
Prepare the filling. In a small saucepan, warm honey until it’s runny but not boiling. Stir in the butter until melted and glossy. Off the heat, whisk in the egg and vanilla until smooth.
Assemble. Pour the filling into the cooled crust. Scatter sliced almonds on top in a pretty pattern. If you want extra crunch, a few whole almonds look nice.
Bake again. Return the tart to the oven and bake 18–22 minutes, until the filling is set and the almonds are toasted. If the edges look too brown, tent with foil.
Cool and glaze. Let the tart cool completely, then drizzle with a bit more honey for shine. Slice and serve. Yes, you can eat it warm, but it holds together better when cooled.