Preheat the oven to 350°F (180°C). Mix the flour with the Splenda sugar mixture in a 20 or 23 cm square mold. Add the butter at room temperature in small pieces. Work with a fork to get a crumbly mixture. Spread evenly in the mold and press lightly. Bake for 15 minutes or until the edges of the biscuit are golden. Let cool out of the oven.
Melt the chocolate in the microwave. Add 2 tablespoons of calorie-free Splenda sweetener and mix well. Pour the melted chocolate over the biscuit. Sprinkle with coconut flakes. Add the nuts. Reserve. In a small bowl, mix the cream and sugar with the melted butter. Spread over the nuts with a spoon. Bake for about 15 to 20 minutes, or until the nuts are golden. Let cool out of the oven, then cut into squares. Store in an airtight container.
Freeze if desired.