Throw all the ingredients into a food processor or blender and whizz until smooth.
Pour out into the tin and bake in oven for 20-25 minutes taking care to remove before it starts to brown.
To make the shizzle
Warm the lemon juice with the agave or honey over a low heat. Taste and add more sweetener if necessary. Pierce the cake a few times with a fork and pour drizzle over the cake while still warm.