Make the crust: Preheat the oven to 375°F. Grease an 8x8-inch baking dish with coconut oil.
In a food processor fitted with the steel blade, process the oats, brown rice flour, coconut sugar, psyllium husks, cinnamon, baking powder, baking soda, and salt for 20 seconds. Add the coconut oil, applesauce, and egg yolk. Process to combine. Using moist hands, pat half of the dough firmly and evenly into the greased baking dish. Crumble the remaining dough into a bowl and mix in the pecans and raisins. Set aside.
Make the filling: In a medium bowl, mix together the blueberries, honey, lemon juice, and arrowroot starch. Spoon the blueberry mixture evenly over the crust.
Finish and bake: Crumble the remaining dough over the blueberry layer and press gently to adhere.
Bake for about 25 minutes, until golden brown. Cool completely at room temperature, then refrigerate for 1-2 hours before cutting into bars. These bars are best stored in the refrigerator or freezer.