Chocolate Icing - unsalted butter

Method

• Heat the butter and chocolate in a bowl over a double boiler.
• Stir constantly with a rubber spatula or wooden spoon until the butter and chocolate are fully melted and combined.
• Remove the bowl from the heat and add the cocoa powder and vanilla, whisking until combined.
• Add half the confectioners sugar and continue to whisk.
• (If the mixture gets too thick to whisk, you can use a spatula or spoon, but be sure to incorporate all the sugar.)
• Add half the sour cream and mix with a rubber spatula until combined.
• Then add the remaining confectioners sugar and mix until combined.
• Begin to add the remaining sour cream, stirring constantly and adding more until youve reached a desired consistency for the icingsmooth and spreadable, like peanut butter.
• (If the climate is hot or humid, not all the sour cream will be necessary.)
• Let the icing chill in the refrigerator for 20 to 30 minutes before using.
• The icing can be kept in an airtight container in the refrigerator for up to 4 days.
• Beat in a mixer or stir vigorously with a rubber spatula for about 2 minutes before using.
• This is a difficult icing to use for a summertime picnic or other occasions that may take place somewhere hot.
• If you want to use it for those occasions anyway, just keep the dessert in the shade and be prepared for the icing to get really soft.
• If you use the icing sparingly between cake layers, the heat wont affect the construction of your cake.
• Also, try using only 2/3 to 1 cup sour cream (as opposed to the 1 1/3 cups called for) to make a thicker icing.