Start with scalding your milk, make sure it just starts to stick to the pot. Defiantly watch it doesn't burn. In a different bowl mix sugar, salt and flour until all combined. The while whisking milk add dry mix and cook for two minutes stirring constantly. you don't want lumps. Keep stirring and add beaten egg yolks and vanilla. Mix till thick and smooth, should almost look glossy. then add sliced bananas and cool.
Whip whipping cream with a mixer and add sugar and vanilla, mix on high until you form stiff peaks. don't over mix and place in separate bowl in fridge.
Once everything is chilled, fill a graham cracker crust ( i always pre buy them) with your filling and top with whipping cream and some sliced bananas :) cool until your ready to serve and slice:) if your having trouble cutting the pie, run your knife through hot water it makes it way easier :)