To the bowl of a stand mixer add the softened butter and sugar. Cream together on high speed for 5 minutes until light and fluffy. Add the egg and egg white and mix until thoroughly combined.
In a large bowl sift together the einkorn flour, cream of tartar, baking soda and salt. Mix together until combined then fold into the wet ingredients. Mix only until no dry spots are visible. Cover with plastic wrap and let rest in the refrigerator for 1 hour. Einkorn takes more time to absorb liquids than conventional flour and needs a resting period.
While the dough is resting, prepare the filling. In a large bowl combine the apple slices, sugar, 1 tsp cinnamon, nutmeg and lemon juice. Stir until ingredients are evenly mixed.
Heat butter in large pan over medium-high heat then add apple mixture and heat until bubbly. Reduce heat and simmer 5-6 minutes until apples begin to soften. Sprinkle flour evenly over apples and cook until sauce thickens. Remove from heat and set aside. NOTE: When working with fresh fruit, the amount of thickener you need depends on how ripe the fruit is. If you’re using super sweet, ripe fruit, increase the flour by 1 or 2 Tbsp.
Preheat oven to 350 degrees. Spray an 8” square baking dish with cooking spray and set aside. In a small bowl combine the remaining 2 Tbsp sugar and remaining ½ tsp cinnamon.
Pour apple filling into baking dish. Scoop walnut sized balls of cookie dough and roll in cinnamon sugar. Arrange cookies on top of apple filling and flatten slightly. Entire top does not need to be covered. The cookies will expand.
Bake 26-30 minutes or until cookie top is lightly golden brown and set. Serve warm with vanilla ice cream.
One Last Thing
We served our snickerdoodle apple crisp with vanilla ice cream, but pick your favorite! There are a zillion ice cream flavors to fit the bill with this tasty treat!