Making the Pies

• Cream pies are made by combining the ingredients needed to flavor the pie -- for instance, chocolate, coconut or lemon -- with heavy cream, butter, sugar, egg yolks and corn starch, all of which is cooked on the stovetop to make a pudding-like mixture or custard. The mixture is poured into the crust and then cooked for 10 to 15 minutes to help the firm up the custard and to brown any meringue topping the pie. The pie is then set in a refrigerator to chill and become firm enough to slice cleanly.

Choosing Subs

• Possible substitutes for heavy cream include a milk-and-butter combination, which is perhaps the most common, and the half-and-half-plus-butter combination, which can be used in a pinch. The whole-milk-and-butter combination renders the best custard.

Making the Substitution

• When heating the mixture of ingredients to make the custard, pour in 2/3 cup of whole milk and 1/3 cup of butter to replace every cup of heavy cream required in the recipe. You may have to do a little fraction math to get an exact measure of the substitute needed. Usually only one cup of cream is needed. Check your recipe to be sure.

Tweaking the Recipe

• You can melt the butter and add it to the custard or add the butter and let it melt as the custard cooks and thickens. The former is probably the faster method. There is a difference in the butterfat content of cream and that of whole milk, which is why the butter is needed. The milk-and-butter combination will contain more water than the cream and slightly less butterfat; this may require you to cook the custard and bake the pie a few minutes longer to dry up the excess water.