In small mixing bowl, combine eggs, milk, sugar substitute and vanilla. Whisk until mixed. Place six, 6-ounce custard cups in 2-quart square baking dish. Divide egg mixture among custard cups; sprinkle with allspice.
Place baking dish on oven rack. Pour boiling water into baking dish around custard cups to a depth of 1".
Bake 30 to 45 minutes or until a knife inserted near the center of each cup comes out clean. Remove cups from water. Cool slightly on wire rack before serving, or cover and chill until serving time.