Preheat the oven to 180°C/160°C fan/350°F/gas mark 4. Grease a 23cm / 9inch square cake tin and line with baking parchment, making sure that you leave some overhanging so that you can easily lift the baked bars out of the tin.
Start by making the shortbread. Whisk together the softened vegan butter and the caster sugar with an electric mixer until it is light and fluffy.
Sift together the plain flour and cornflour (cornstarch) then add them to the butter mixture. Stir with a spatula until it forms a dough, it may seem like it is too much flour but it will combine eventually.
Tip the dough into the prepared cake tin and use your hands to pack it down as firmly and as evenly as possible.
Bake the shortbread for about 30 mins until it is golden brown. If it has puffed up at all press it back down gently.
While the shortbread is baking prepare the lemon curd. Place the cornflour in a non-reactive saucepan and gradually whisk in the lemon juice to make a smooth paste. Whisk in the lemon zest, sugar and coconut cream.
Place the pan over a medium heat and stir constantly until it comes up to the boil and thickens considerably.
Remove from the heat and add the butter, stir until it has dissolved then straight away pour the lemon curd over the baked base. Spread it level and leave to cool for about 30 minutes until it is set.
To make the frangipane, whisk together the ground almonds, plain flour, cornflour, baking powder and sugar.
Add the milk, melted butter, lemon zest and almond extract and whisk until smooth.
Spoon the frangipane on top of the set curd and spread it level, scatter over some flaked almonds if you like.
Bake for 40-45 minutes until golden and a skewer inserted into the centre (but not as far as the lemon curd) comes out clean or with a few moist crumbs but no wet batter.
Leave to cool in the tin for 30 minutes then carefully lift out using the overhanging baking parchment and place on a wire rack to cool completely. Once cold, slice into bars or squares and serve. Best on the day they are baked.