Preheat the oven to 350°F. Lightly coat a 9x13" glass baking dish with coconut oil.
In a large saucepan, add the blueberries and the tapioca flour. Mash the berries with a potato masher and heat them over medium heat.
Bring the mixture to a simmer and continue to mash the berries. Simmer and mash until the mixture thickens. Turn off the heat.
In a large mixing bowl, beat together the peanut butter, maple syrup, coconut sugar, eggs, and coconut milk. Add the baking powder and sea salt and beat until smooth.
Add the rolled oats and beat the mixture until everything is incorporated.
Spread a little over 1/3 of the mixture into the bottom of the glass baking dish. Spoon the jelly mixture into the pan and spread it out evenly.
Place spoonful's of the remaining peanut butter mixture on top of the jelly layer. Dip a spoon in some water and carefully spread the peanut butter mixture over the jelly using the spoon. Re-wet the spoon as needed to help with spreading the mixture.
Bake for 30-35 minutes. The blueberry mixture should be bubbling slightly and the edges of the bars should be lightly browned.
Cool immediately. Once cool, you can cut the bars! Store in an airtight container at room temperature or in the fridge.