Make biscuits: In a bowl, stir together dry ingredients. Add in cold cubed butter and using a pastry cutter or your fingers break up the butter into the flour mixture until it is in small pieces.
Add in applesauce, egg , and butter and mix to completely combine. Using your hands, roll dough into 6 balls and then using your hands pat the balls into a biscuit shape about 2-1/2" in diameter and set aside.
In a large bowl mix together the blueberries, strawberries, lemon zest and juice, arrowroot, lemon and sugar until well combined and pour into a 9 x 13 inch baking dish or large cast iron skillet.
Top berries with the the biscuits. Sprinkle biscuits with extra sugar if adding.
Cover lightly with foil and bake for 20 minutes. (See note on how to cook frozen fruit) Remove the foil and bake for an additional 20 minutes. Serve warm with a big scoop of vanilla bean ice cream!
Can you omit the arrowroot? It helps thicken the berry mixture! It will be watery without.
You can use a mix of other berries, too!!
If cooking with frozen fruit, bake an extra 10 minutes uncovered.