Preheat oven to 350F and line a 9x9 pan with nonstick foil.
Beat butter and sugar until light and creamy.
Add vanilla, flour, graham crumbs.
Press 2/3 of this dough into the pan.
Spread on the Nutella with an offset spatula.
Dollop the fluff on top across the Nutella.
Flatten pieces of the rest of the dough and lay on top of the fluff and Nutella.
Bake for approx 30 mins.
Hot out of the oven I added a few more dollops of fluff.
Cool a bit and eat warm.