What is the cooking term sabayon?

it is a dessert sauce made with champagne served as part of tierra misu

Sabayon is made from egg yolks and marsala wine. You wisk the eggs and wine over boiling water with a little sugar until it froths and begins to thicken. Remove it from heat and serve over fresh strawberrys. It has nothing to do with tiramisu. It can be made with something other than marsala wine, like champagne.