In a medium bowl, combine yeast and warm water, stirring until yeast is dissolved.

In a large bowl, whisk together lemon cake mix and flour.

Add the yeast mixture and lemon zest to the cake mix mixture, and stir with a sturdy wooden spoon, or use your hands, until ingredients are combined.

Lightly grease the top, and cover with plastic wrap.

Let the dough rise for 1 hour, then punch it down, and let it rise again for another 30 minutes.

Lightly grease a 9x13-inch pan and an 8-inch square pan.

Turn the dough out onto a lightly floured surface, and roll it into a large rectangle. Mine was enormous - approximately 18x24 inches, and just over 1/4-inch thick.

Brush the dough with the melted butter, sprinkle evenly with sugar, drizzle with raspberry jam, and sprinkle with raspberries.

Roll the dough from the shorter side, so that it forms a log approximately 18 inches long.

Cut into 16 equal-sized pieces. It will get messy, but you can use two hands to lift each piece into the pans. Place 4 in the smaller pan, and 12 in the larger pan.

Bake at 350 degrees for 15-20 minutes, or until the rolls are golden brown at the edges. My rolls were quite large, and it took about 18 minutes, but I think this can vary depending on how you cut the rolls.

Allow to cool for about 10 minutes before spreading with the frosting.

In a small mixing bowl, beat Mascarpone cheese and whipped topping until smooth.

Beat in sugar and lemon zest.

Spread onto the slightly cooled sweet rolls, and serve immediately!