Preheat oven to 350 degrees F. Lightly butter or grease an 8" glass baking dish.
In a blender or food processor, add butter, sugar substitute, eggs, sour cream lemon juice and zest, almond flour and baking powder. Blend until smooth. Pour 1/2 of the batter into the baking dish.
Prepare the filling: In a food processor, fitted with a blade, add softened cream cheese, cottage cheese, 1 egg yolk, sugar substitute, vanilla and almond extracts and blend until smooth, scraping down the sides.
Using a spoon, drop filling in heaping spoonfuls onto the batter. Swirl in filling with knife. Don't worry if it's not completely blended. Pour remaining batter on top.
Bake uncovered in the middle of the oven for 40-45 minutes until golden brown. Souffle will be firm, but slightly soft when done.
Serve Blintz souffle warm with fruit sauce, jam or powdered sugar.