First, preheat oven to 350ºF and line an 8x8-inch pan with parchment paper and set aside.
Next, create your crust and crumble. Mix all crumble ingredients together (minus the coconut sugar, you'll add this later). You're going to want to make sure that the coconut oil is slightly melted, but not liquid. You do this so the dough is more of a crumble, but can still be pressed together into a crust.
Then, take 2/3 of the mixture and press it evenly onto the bottom of your pan. Set the rest of the crust/crumble mixture aside and add 1 tablespoon of coconut sugar. Mix. This is what you will use for the crumble topping.
Bake crust at 350ºF for 10 minutes. Remove crust and set aside.
Next, place all ingredients (except for the tapioca flour) for the strawberry filling into a medium saucepan or cast iron skillet. Turn heat to medium/high and bring the filling to a boil, stirring often and breaking up the strawberries. Once boiling, turn the heat down to low and let simmer for 20 minutes (don't skimp on this! It's important to break down the strawberries or your bars will be too wet.). Continue stirring.
Once the filling has cooked for 20 minutes and has become darker in color, add in 2 tablespoons of tapioca flour and stir until there are no more clumps and the strawberry filling has thickened.
Pour on top of the crust and spread out evenly. Then, sprinkle on the rest of the crumble mixture over the top of the strawberry filling.
Bake for another 20 minutes at 350ºF.
Let cool for 20 minutes before placing into the fridge for at least 2 hours (or for best results, overnight) to let the filling set. Slice and enjoy!