Preheat oven to 350 and spray an 8-inch square metal baking pan with non-stick cooking spray.
In a mixing bowl, beat butter with an electric hand blender until creamy, then mix in the egg. Slowly add the dry cookie mix and blend until all incorporated.
Press the dough evenly into the bottom of the prepared pan. Place the pan in the freezer for 20 minutes, then bake for 20 minutes until the top and edges are golden and set. Transfer to a wire rack and cool completely.
For the topping, combine the chocolate chips and butter in a microwave safe bowl and microwave for 30 seconds. Remove and stir, then continue heating and stirring in 15 second intervals until smooth. Allow the chocolate mixture to cool for 3 minutes, then add the mascarpone and stir until the mixture is creamy and smooth.
Spread the chocolate mixture evenly over the cooled crust and sprinkle with chopped almonds and toffee pieces.
Cover pan and chill in the refrigerator for at least two hours before serving