Preheat the oven to 180 or gas mark 4
Line 2 baking tins with the parchment or greaseproof paper
Cream together the butter and sugar in the bowl until the mixture comes together and is pale yellow, light and fluffy. This usually takes 1-2 minutes.
Add the egg and vanilla, and beat again
Add the flour and lemon zest and mix together
Stir in the blueberries with a wooden spoon
Using a tablespoon, put the mixture onto the baking sheets. Make sure there is space around the mix as it will expand when in the oven.
Put the trays in the oven and cook for 12-15 minutes, or until golden
Cool on a wire rack and enjoy
