Heat oven to C190
Cream peanut butter, butter and sugars together either manually with a wooden spoon or in the electric mixer
Beat in the vanilla and egg
Add the flour, baking powder, bicarbonate of soda and salt to a soft dough
Wrap dough in cling wrap and chill for 30 minutes
Remove the dough and roll into balls about the size of a walnut
Place the balls on the baking paper a little apart from each other as they will swell when baking them. Gently flatten them with you palm to a cookie size
Place the cookies in the oven and bake for 20 - 30 minutes till they are golden brown. If they need more cooking, I suggest you do it in 5 minute intervals