In a large bowl, beat together the butter, golden syrup and sugar until fluffy.
Beat in the egg, lemon zest and lemon juice.
Add the flour and the baking powder and mix well – you should now have a sticky, light dough.
Shape and bake.
Use a small ice cream scoop or rounded tablespoon to scoop up the dough, flattening off against the side of the bowl, then roll the dough into a ball with your hands. This is the best way to get equally sized cookies. You should get about 28, or fewer if you use a larger scoop.
Place the balls of dough on baking sheets lined with greaseproof paper, being sure to place each cookie at least an inch apart so that they don’t stick together when they spread.
Bake for 12-14 minutes until ever so slightly golden at the edges. Get them out of the oven before they’re fully browned so that they stay chewy when cool.
While still hot, place a tumbler over a cookie and gently move it in small circles to bring the cookie into a neat circle. Repeat with all of the cookies - this only works when they are fresh from the oven and soft.
Allow to cool on the tray until firm enough to transfer to a wire rack to cool completely.
Ice the cookies
Put the icing sugar and lemon juice in a bowl. Whisk until you have a thick, lump free icing.
Drizzle back and forth over the cookies.
Scatter the grated lemon zest over the top and allow to set.