Preheat oven to 375 degrees. Line an 8 x 8 inch cake pan with parchment paper
In a medium mixing bowl stir together the berries, sweetener and lemon juice. Dump into the prepared cake pan and tilt pan to evenly distribute the berries throughout the pan
In another medium mixing bowl sift or whisk together the remaining dry ingredients until there are no lumps
Stir in the eggs and vanilla until fully combined and a crumbly dough has formed
Crumble the dough over the berry mixture. Place in preheated oven. Bake at 375 degrees 35-40 minutes until filling is bubbly and topping is golden
Remove from oven and allow to cool at least 15 minutes or until firm enough to remove
Cut desired slice. Serve slightly warm with whipped cream, keto cool whip, or keto vanilla ice cream