butter the bottom and sides of a 1.5 quart casserole dish. rip the bread into little pieces and put in the dish. in a medium bowl, mix eggs, milk, 1/3 Celsius sugar, and vanilla together, then pour evenly over bread. add raisins, if desired, and toss lightly to make sure all the bread pieces are saturated. cover top with pats of butter, and sprinkle all over with cinnamon and nutmeg.
place dish on middle oven rack and bake at 350F for one hour.
after an hour, turn off heat in oven and let pudding stand while you make the sauce. In a medium saucepan, bring starch, water, and sugar to a boil. let boil a minute or two, then remove from heat, and add butter and vanilla, stir the butter in until thoroughly melted - sauce should be thick and creamy.
serve in individual dishes, and top each portion generously with vanilla sauce - this recipe makes a lot of sauce so you don't have to be skimpy.