Nigella’s - mine has never sunk. I add an extra tsp of baking powder.
125g butter
175g sugar
Cream together til white. Add zest of 1 lemon.
Add in 2 eggs, a bit at a time (I use an electric whisk all through).
Add 175g of flour a bit at a time. (This is where I add an extra tsp of baking powder.)
4tbsp milk to slacken.
Put in a lined load tin, pref with one of those nice loaf tin liners.
Bake for 45mins at 180degrees or 160 degrees fan. Might take up to 55mins depending on your oven. Check it’s done with a skewer.
While baking juice 1.5 lemons and add 100g sugar. Stir til as dissolved as possible.
Once out, poke holes with said skewer and pour on lemon juice mix, slowly and carefully covering the whole whole cake.
This has won complements at the WI.