In a medium mixing bowl, stir together 1 1/2 cup almond flour, 2 Tbsp coconut sugar, 1 stick grass-fed butter, 1/2 tsp almond extract, a pinch of salt.
Add the butter, and stir together by hand until the mixture has fully combined. You will end up with a big ball of dough.
Transfer dough to a greased 9-inch tart pan with a removable bottom. Using your fingers with the help of plastic foil, evenly press dough in bottom and up sides of the pan.
Bake on the middle rack of oven until golden and firm, about 15- 20 minutes. Transfer to a wire rack to cool completely, at least 1 hour.
Make the cherry filling
In a small mixing bowl, stir together ¼ cup almond flour, ¼ cup coconut sugar, lemon juice and 1/2 tsp vanilla. Add pitted cherries and stir well.
Transfer cherry filling to cooled crust and spread out evenly.
Make the topping
In a medium mixing bowl, stir together 1 cup almond flour, 1/2 cup coconut sugar, and ⅛ tsp salt. Add 1 stick diced cold butter to the mixture and mix everything with your hands until butter is pea-sized.
Add ½ cup gluten-free oats and use your hands to make large crumbs, rubbing the mixture between your fingers. Add ½ cup sliced almonds and toss to combine.
Spread the crumble topping evenly over the cherries, and sprinkle on the second ½ cup sliced almonds. Bake uncovered at 350˚F for about 20 minutes, or until almonds are golden brown. Let the almond cherry crumble tart cool at least 15 minutes before serving.