In a small saucepan combine the lemon juice and the sugar. Simmer over low heat until the sugar has dissolved and the volume has reduced by half. Allow to cool slightly.

Lay the slices of cake on a parchment lined baking tray. Using a pastry brush, glaze each slice of cake evenly. The glaze should be syrupy but thin enough to soak into the cake.

In the bowl of a stand mixer fitted with the whisk attachment, combine the oil and sugar. Beat on high speed for a minute.

Add the flour and almond extract. Whisk briefly to combine.

Add the aquafaba one tablespoon at a time, whisking well between each addition. After the final addition, scrape down the sides and beat again for a minute. The mixture wont increase in volume like meringue but it should be lovely and smooth and glossy.

Remove the bowl from the machine and fold in the ground almonds with a spatula.

Preheat the oven to 180c.

Divide the jam between the four slices of cake and spread evenly right to the edge of each slice.

Divide the frangipane batter between the four slices and top roughly (it can be quite tricky to work with but a wet teaspoon should make it easier to spread). You don’t have to spread right to the edge, in fact it can be nice to leave some jam visible around the edges.

Divide the berries between the four slices and press lightly into the frangipane, making sure they’re still visible. Top with a sprinkle of flaked almonds and place in the oven for 25-30 minutes until the frangipane is puffy and browning on the edges.

Remove from the oven and allow to cool completely. Sprinkle with icing sugar and serve.