Grease 4 ramekin dishes (125ml) with a little extra reduced-fat spread.
Place the self-raising flour, spread, sweetener, eggs, lemon flavouring and lemon juice into a mixing bowl. Beat together for 1-2 minutes, using an electric whisk or wooden spoon until smooth and creamy.
Divide the mixture between the ramekin dishes. Drop a teaspoonful of lemon curd into the centre of each.
Place all 4 ramekins into the microwave. Cover loosely with cling film and cook on high for 1½-2 minutes. Check on the cakes after about a minute and continue cooking if needed. The cakes will be ready when they're risen and spongy but still runny in the centre. Leave to stand for 5 minutes, then remove the cling film.
Sprinkle with the lemon zest and a little icing sugar if you like. Serve alone, or with a swirl of reduced-fat aerosol cream or a little custard.