Preheat the oven to 350 degrees Fahrenheit and line a 9” x 9” baking pan with parchment paper. 

Stir all of the ingredients for the crust and topping in a mixing bowl until it is well combined and a thick sticky dough forms. If you'd like, you can use an electric mixer, but it isn't necessary. The dough may seem very crumbly - this is normal.

Measure out ¾ of a cup of the mixture and set it aside to use as the topping later. Transfer the remaining almond flour mixture to the parchment-lined pan and press it into an even layer with your hands. 

Use a fork to poke many holes in the crust. This will allow it to bake evenly as there will be some airflow through the crust. 

Bake on the center rack of the preheated oven for 10 to 12 minutes, or until the crust is lightly golden brown. Remove the crust from the oven.

While the crust is baking, you can prepare the blueberry filling. Transfer the blueberries and a pinch of sea salt to a saucepan. Cover the saucepan and heat it over medium heat on the stove top, stirring occasionally. After a few minutes, liquid will begin to leach out of the blueberries. Once this occurs, you can mash the blueberries with a spoon or fork to help along the process.

Add the tapioca flour and sugar-free sweetener and stir well to combine. Allow the mixture to boil for a couple of minutes to thicken, then remove it from the heat.

Transfer the blueberry filling to the pan and smooth it into an even layer over the crust, creating the blueberry layer.

Use the reserved crumble mixture to sprinkle over the blueberries. Note: you can leave the mixture very crumbly or you can press it into small dough nuggets, depending on the look you’re going for. I do a combination of both.

Bake the bars at 350 for 22 to 30 minutes or until the topping is golden-brown and the blueberry filling is bubbly.

Remove the bars from the oven and allow them to cool for at least 30 minutes before slicing and serving. Store any leftover Keto Blueberry Crumb Bars in an airtight container in the refrigerator for up to 7 days.