The success of this recipe depends upon the melted chocolate and butter being at the same temperature. If not, the chocolate and butter will separate.

Melt the chocolate either in the microwave or in a bowl over a pot of simmering water. Stir in the Splenda and cool to room temperature. Combine the chocolate and butter until smooth. Stir in cream and vanilla, then the nuts if using.

Spread evenly into a small, parchment lined loaf pan. Chill until firm. Cut into pieces and store in the freezer.