Traditional ganache calls for only two ingredients -- chocolate and heavy whipping cream. When melted together, these ingredients form a thick, glistening sauce that can be used to frost cakes and cookies, top ice cream or even make truffles. The sauce thickens as the melted chocolate solidifies. There's no reason you can't substitute half-and-half for whipping cream, but the finished product will be different.
The main benefit of substituting half-and-half for whipping cream is to your waistline. Whipping cream has a whopping 414 calories per cup and 44 grams of fat, including 28 grams of saturated fat. Half-and-half, which is half milk, half cream, has 315 calories per cup and 28 grams of fat. Some blends made with skim milk have even fewer calories and fat. Half-and-half also usually costs less than heavy cream.
Because half-and-half contains milk, ganache made with it will be thinner and have a lighter texture. This thinner ganache can't be used for making truffles, but it's ideal for frosting a cake or as an ice cream topping. Flavorings, such as vanilla, raspberry liquor or peppermint extract also improve the taste. Experiment with different types of chocolate to find the one that suits you. Dark chocolate makes a very rich, slightly bitter ganache, while semi-sweet makes a standard ganache. Milk chocolate ganache has a mild, sweet taste.
When substituting half-and-half for whipping cream in ganache, use the same amount of half-and-half as you would cream. A typical recipe calls for 1 cup of half-and-half to 12 ounces of chocolate. Mixing the two together is a cinch. Simply heat the half-and-half until it's almost boiling and pour it over the chocolate. Stir it occasionally until the chocolate melts and becomes fully incorporated in the half-and-half. Because half-and-half has milk in it, it curdles more easily than whipping cream when exposed to high heat. Don't allow it to reach a boil. Another problem worth noting is that of seizing. Seizing happens when a little liquid is added to chocolate, causing the chocolate to clump together in an unappealing mess. You can avoid this problem by adding the half-and-half all at once to the chocolate, or by pouring the chocolate into the liquid and whisking until smooth.
Half-and-half can stand in for heavy cream in ganache, but it's not your only option. Evaporated milk, which is canned milk that's been heated to remove 60 percent of the water, has a creamy texture but only 340 calories and 10 grams of fat per cup. It can easily stand in for heavy whipping cream in ganache and it has the added benefit of being shelf-stable. Sweetened condensed milk is sometimes used to make an ultra-sweet, ultra-thick ganache suitable for fillings.