In a mixing bowl, pour melted butter, add soft brown sugar, stir and then add egg, peanut butter and stir.
Add roasted corn flour, baking powder, ginger powder, salt, vanilla essence and mix into a dough.
Wrap in a cling film and set in the fridge for 30 minutes.
Pre-heat the oven at 180 degrees celcuis.
Take the dough out and mold into golf ball size.
Line a baking tray with a parchment paper and place the molded balls on, well spread apart.
Press the cookies with the back of a fork to squash them a little.
Bake for 12-15 minutes or until golden.
Cool on a tray, then transfer to a wire rack and cool completely.
Peanut butter cookies ready to serve.