Step 1
Position the oven shelves towards the centre of the oven. Preheat the oven to 180°C/fan oven 160°C/Gas Mark 4. Lightly grease two 18cm (7in) sandwich tins with a little Trex, line their bases with a circle of greaseproof paper, then lightly grease the paper.

Step 2
Sift the flour, baking powder and salt into a mixing bowl. Add the sugar, Trex, unbeaten eggs, milk and vanilla extract. Use a wooden spoon to beat the mixture together until smooth and creamy – this will only take 1-2 minutes.

Step 3
Share the mixture equally between the prepared tins and level the surfaces. Bake for 18-20 minutes. To test that the cakes are cooked, they should be golden brown, and when touched lightly the tops should spring back into place. Put the tins on to a wire rack to cool for a few minutes.

Step 4
Remove the cakes from their tins and cool on a wire rack, then remove the lining paper. When completely cool, sandwich the cakes together with strawberry or raspberry jam and whipped cream and sprinkle the top with caster sugar. Alternatively, make the lemon filling by mixing together the lemon curd, mascarpone cheese and lemon juice with the lemon zest until smooth and creamy. Use instead of the jam and cream.