Preheat oven to 375 degrees F (190 degrees C). Butter a 9x13-inch casserole dish.
Spread cranberries out in the bottom of the prepared casserole dish.
Whisk milk, cream, eggs, and egg yolks together in a bowl; add white sugar, orange liqueur, vanilla, and salt. Gradually add flour, whisking constantly. Pour egg mixture through a sieve over cranberries in casserole dish.
Bake in the preheated oven until cranberries are set and clafouti is set, about 45 minutes. Dust with confectioners' sugar.
