Pre-heat oven to 375°F. Put blueberries in a bowl and combine with lemon juice, zest, sugar, arrowroot and salt. Gently mix, you don't want to break all the blueberries, but a few will be ok.
Evenly distribute the blueberries into each ramekin.
Combine topping ingredients. Make sure the coconut oil is softened or melted for easy mixing. The texture of the dough should be crumbly and somewhat dry. It shouldn't be one heap of dough or batter-like. If it's too wet, add more coconut flour, 1 tbsp at a time until it is crumbly.
Sprinkle the crumbles of dough on top of the blueberries in the ramekins until they're covered. There may be a little leftover sough, but don't overload the blueberries…you don't want an uneven ratio of crumbles to blueberries. Place ramekins in the oven on a cookie sheet or about 15-25 minutes.