Preheat the oven to 350 degrees.

Roll out the pie crust and cut out 24 circles with a 2.5 inch biscuit cutter. (63mm)

Heavily grease a mini muffin pan with non stick spray. Then place each circle of pie crust into a spot on the pan.

Dice the apples very small. Then sprinkle with the lemon juice from the half of the lemon so that the apples don't brown while you assemble the dessert. Fill each muffin tin with the apples. You don't want them mounded up, you need room for the crisp topping. Just make sure each one is filled with an even amount of apples.

In a food processor fitted with the steel blade combine the brown sugar, oats, almond flour, cinnamon, five spice, vanilla, salt and butter. Pulse for 20-30 seconds or until well combined. Using a 1/2 tsp measure a heaping amount into each muffin tin. Pressing down to top the apples. Continue until all of the tarts are covered with crisp topping.

Bake for 20 minutes or until nice a golden brown.

Allow to cool in the pan for five minutes. Then using a knife carefully get the tarts out of the pan and allow them to continue to cool. You might have a few casualties with sticking but most come out just fine.

Top with a teaspoon of vanilla ice cream if desired.