Ingredients: 

1/2 cup unsalted butter, softened

1 (8 ounce) cream cheese, room temperature – or Tofutti lactose free cream cheese (Sprout’s)

1/2 cup creamy peanut butter (omit if you don’t like peanut butter)

1 teaspoon vanilla extract

2½ cups confectioners sugar

2 tablespoons heavy cream

Instructions:

Combine butter, cream cheese and peanut butter in a mixing bowl and beat with an electric mix...

If you live somewhere like the U.K., then yes, you can find double cream. Double cream is used quite often in the U.K.

In the U.S., a close substitute would be heavy cream, or heavy whipping cream (both the same thing, just two different names)...