Remove the flapjack from the oven and immediately use a rolling pin to lift the marzipan on top. Press down gently, keeping a flat top, but the heat from the oats should stick the marzipan to them. Peel away the paper from the sides of the flapjack and discard. Now heat the grill to a low-medium heat, or if you have a blowtorch, fire it up. Scorch the marzipan so it’s crisping and turning caramel brown, but be careful not to burn. Cool the whole flapjack in the tin completely, then cut into 20 large bars or 40 small.