Prepare your baking pan by coating it with baking spray, or a layer of grease and flour.
Make the batter
Add the sugar and lemon zest to a bowl and rub the zest into the sugar. Cover the bowl and set aside for 30 minutes.
Add the flour and baking powder to the sugar and whisk together until combined.
Add the oil and mix until combined.
Add the eggs and mix until combined.
Add the lemon extract and lemon juice, and mix until fully combined.
Add the batter to the pan and tap it on the counter a few times to make it even on top. If you have a sculpted pan, this also helps to fill in any air bubbles in the top design.
Bake until the batter reaches 205°F (96°C) on a probe thermometer. The cake will spring back when touched with a finger, and a cake tester will come out mostly clean.
Let cool in the pan for about 10 minutes. Then, put a cooling rack on top of the pan and flip them over together so the cooling rack ends up on the bottom. Carefully remove the pan from the cake and let cool.
Whisk the powdered sugar and lemon juice together until there are no more lumps.
While whisking constantly, drizzle the melted cocoa butter into the sugar and lemon juice mixture.
Put a piece of parchment paper or foil underneath the cake to catch drips. Drizzle the glaze onto the cake, or brush it on with a pastry brush.
Uncut, this cake will keep about 3-5 days at room temperature. It also freezes very well, wrapped and stored in an airtight container. You can keep it in the freezer for several months.