Preheat the oven to 180°C, fan 160°C, gas 4.
In a bowl, mix together the melted butter, flour, sugar, eggs, and 4 teaspoons of the lemon extract. Divide between 8 mini loaf cake cases and bake for 25 minutes. Cool slightly, then remove the cases.
In a bowl, mix the caster sugar with the icing sugar, 50ml cold water and the remaining lemon extract. Pour over the warm cakes, and scatter with lemon zest to serve.
Cook’s tip: if you don’t have mini loaf cases or tins you can make lemon drizzle muffins by simply using a muffin tray lined with muffin cases.