In a large jug, stir together the egg yolks, milk, flour, baking powder and salt with a fork. Add the ricotta to the jug and mix just a little (seriously like 3 stirs; you want tasty ricotta lumps). In a large bowl, whisk the egg whites until stiff. Pour the contents of the jug into the large bowl and fold in using a rubber spatula. There should be some lumps of ricotta throughout.