While the cake is still frozen, use a large serrated knife to slice it lengthwise into 2 equal layers. Set aside.
Place the cream cheese and the powdered sugar in a small bowl, and stir to mix well.
Lay the cake layers on a flat surface, cut sides up. Spread half of the cream cheese mixture on the top of each layer.
Place the strawberries in a large bowl, and sprinkle with the sugar.
Overlapping the strawberries, arrange a layer of strawberries over the cream cheese only on the bottom half of the cake. About 1 cup of strawberries should be left over. Set aside.
Reassemble the cake by placing the top half over the bottom half so that the strawberries are sandwiched between the 2 layers of cream cheese. Wrap securely in plastic wrap, and chill for at least 1 hour, or until ready to serve.
While the cake is chilling, place the yogurt in a small bowl, and stir in any remaining strawberry slices. Chill for at least 30 minutes, or until ready to serve.
To serve, slice the cake into 8 portions, and place each slice on an individual serving plate. Spoon some of the yogurt sauce over each slice, and garnish with a strawberry half and a mint leaf. Serve immediately.
Prep Time: 20 mins.