Beat all ingredients in a large bowl on medium speed until the mixture is smooth.
Pour the mixture into an 8-inch round cake pan coated with cooking spray, cover the cake pan with aluminum foil, and place in a larger baking pan. Pour hot water into the larger baking pan to a depth of 1 inch.
Bake for 1 1/4 hours or until a knife inserted in the center comes out clean. Remove the pan from the water bath, uncover, and let cool on a wire rack for at least 30 minutes.
Serve at room temperature or cover and refrigerate overnight. Loosen the edges with a knife and invert the custard onto a serving plate.