Cream the butter and sugar together in a large bowl.
Add the flour, baking powder, oats, toasted sesame seeds, honey and vanilla essence and mix well.
Place a non stick baking sheet on a metal baking tray.
Spoon the mixture into a biscuit cutter on the baking sheet and flatten down with the back of a spoon to a thickness of 7mm. Leave a space of 2cm to 3cm (about 1") between each biscuit to allow room for expansion.
Bake in batches in the centre of the oven at 180C, 350F, gas mark 4 until cooked, this will take about 8 minutes. Check after 5 minutes and then check again regularly as the biscuits cook quickly. Turn the tray around after 5 minutes. The biscuits will be cooked when they start to turn golden at the edges.
Leave the cooked biscuits on the baking tray for 5 minutes then transfer to a wire cooling rack.