1 cup unsalted butter, softened
2 cups white sugar
4 eggs
1 teaspoon vanilla extract
2 cups confectioners' sugar for decoration
Melt butter with both shortening and sugar in a medium saucepan over medium heat. Stir until all the butter has melted and all the sugar is dissolved. Stir in the eggs one at a time, then stir in Vanilla. Bring to the boil, then remove from heat.
Pour the confectioners' sugar into a small bowl and together they will form loose balls.
Bake for 8 to 10 minutes in the preheated oven, until thick and sticky. Cool completely before spread. Use a large shallow dish for best results.