Mix Keto Chow and water.
Cut cream cheese into small pieces, then mix the berries, bread, and cream cheese together. Place half of the mixture in a greased 9×13 pan.
Beat eggs, the mixed Keto Chow, maple syrup, and vanilla. Pour half of this mixture over the bread in the pan. Put remaining bread mixture on top and pour remaining milk mixture on top and press down with a fork.
Cover and chill overnight or eight hours. Remove from fridge 30 min before baking.
Preheat oven to 350℉. Bake covered 30 min and then uncovered 30 min.
To make the sauce, mix together the powdered erythritol and glucomannan.
Add water, mix well, and bring to a boil, stirring constantly.
Add blueberries. Reduce heat, simmer 8-10 minutes until fresh berries burst. Stir in butter until melted and incorporated.
Pour sauce over the casserole before serving.