Pre-heat oven to 350 degrees farenheit. Grease and flour a 8 inch pan(depending on how thick you want the brownies)
Melt the butter (I reccomend a microwave,but a saucepan works too) and stir in a large bowl; vanilla ,eggs , the melted butter , cocoa powder , baking powder, salt and flour,pour into the greased pan and set aside.
Whick together all the ingredients for the Lava layer in a seperate bowl.Once mixed pour the lava layer over the brownie batter.
Bake in the pre-heated oven for 25-30 minutes until the batter no longer jiggles in the middle(Do not overcook, but if it is still fairly jiggly put it in for a few more minutes, but watch it like a hawk)