Using a fork, mix together ingredients until they form a crumb like consistency and set aside.
In a bowl, combine dry ingredients. With the mixer on low, gradually add in coconut oil a tablespoon at a time. Once the mix is crumbly, add in vanilla, coconut nectar and slowly add in water 2 tablespoons at a time.
Remove from bowl and form into a ball shape and flatten into a disk. Oil & flour bottom of pie plate, place disk into pie plate, using either the heel of your hand or pastry roller, press out into the bottom and sides of the plate; then use your hands to form crust and crimp edges. With a fork poke a few holes in the bottom of the crust.
Preheat oven to 350°. Place crust in refrigerator until it hardens up (usually about 15 minutes, enough time to chill while you are making the filling).
Place filling ingredients minus the arrowroot/water in a pot over medium heat stirring frequently as the fruit releases moisture. After the strawberries and rhubarb have cooked down, mix together the arrowroot and water to form a slurry.
Immediately, pour it into the Strawberry/Rhubarb mixture. Keep on heat and stir until mixture thickens. You'll be able to feel it thickening as you stir, be careful to stir until it's evenly combined & thickened.
Place the piecrust in the oven and bake for 5 minutes without the filling. Remove from oven and fill with the Strawberry/Rhubarb mixture and top with crumb coating.
Bake for 30 minutes. Let cool before placing in fridge. Allow pie to set up overnight before enjoying.