A hedgehog slice is a type of Australian dessert or snack that looks like a dense brownie but actually is made primarily of crushed cookies or other crisp dessert confections that are bound together by a mixture of butter, cocoa powder or chocolate and other ingredients. The mixture is not cooked in an oven but is a variety of refrigerator cake that is chilled until set. Most often, the top of the hedgehog slice is coated in frosting or dusted with shredded coconut, sprinkles or nuts. In Australia and some areas of New Zealand, hedgehog slice is regularly sold at coffee shops, restaurants and other stores as a sweet treat.
One of the main components in a hedgehog slice is some type of cookie. Different recipes call for different types of cookies, and there is no single correct choice. In general, however, the cookies that are used are pale in color to contrast with the rest of the slice, and either lightly flavored or unflavored. Vanilla, hazelnut, ginger, graham crackers and shortbread are all options that can be used to make a hedgehog slice. Ultimately, however, the decision is up to the taste of the cook.
The first step in making a hedgehog slice is to place butter and sugar in a pan and heat the mixture slowly until all the sugar has melted and the liquid is smooth. White sugar or brown sugar can be used. Cocoa powder or pieces of chocolate and any other flavorings, such as vanilla or coconut, are added to the mixture and blended until well incorporated. The entire mixture is then allowed to cool slightly.
Once cooled a bit, but while still somewhat warm, eggs or egg yolks are added to the chocolate mixture. The mixture needs to be hot enough to warm the eggs through, but not so hot that the eggs instantly solidify when added. The eggs can be tempered first by stirring in a small amount of the warm mixture before adding them in the pan or, alternately, the eggs can be beaten and warmed slowly over a double boiler. In addition to preventing the eggs from curdling into solid pieces, this step also heats them enough to remove any salmonella that might be present.
Once these ingredients are combined, the chocolate mixture is combined with the crushed cookies, poured into a baking pan or other dish and placed into a refrigerator until it has set. Toppings can include chocolate icing, tempered chocolate, sugar sprinkles, coconut or powdered sugar. The completed hedgehog slice can be cut with a warm knife and served on a cake or stored in the refrigerator for later use.