Spread the batter evenly on the prepared baking sheet using an offset spatula. The cake batter should be evenly thick and spread to all corners of the pan.
Bake for 20-25 minutes in the preheated oven.
Make the whipped cream filling by combining the mascarpone, heavy cream, and monk fruit sweetener in a medium bowl. Using an electric mixer on medium speed, whip until the mixture is smooth and holds soft peaks.
Add fresh fruit if desired. Gently fold chopped strawberries into the cream cheese mixture for extra flavor and texture.
While the cake is still warm, run a knife around the edges to loosen it, if needed. Quickly invert the cake onto a clean surface (like the kitchen countertop or a clean tea towel) and gently peel away the parchment paper.
Roll the cake while it's still warm. Starting from one of the short ends, carefully roll the cake with the towel. This helps the cake "remember" its shape. Place on a wire rack or cooling rack and let it cool completely.
Unroll the cake carefully once it's completely cool. The cake should unroll easily without cracking if properly cooled.
Spread the filling evenly over the surface of the cake, leaving about ½ inch border around the edges.
Roll the final cake starting from the same short end, rolling tightly but gently. The cream should just reach the edges without squeezing out.
Chill and serve. Wrap the whole cake in plastic wrap and refrigerate for at least 2 hours or overnight.
Before serving, remove plastic wrap and decorate the top of the cake with fresh berries and almond flakes.