Healthy Blueberry Coffee Cake

Preheat the oven to 350 degrees F and line an 8" x 8" cake pan with parchment paper.
Stir together the almond flour, coconut flour, baking soda, and sea salt in a large mixing bowl. Add the wet ingredients (eggs, pure maple syrup, coconut milk, melted coconut oil, and vanilla extract) to a separate mixing bowl. Whisk to combine.
Pour the dry ingredients into the bowl with the wet ingredients and stir well until a thick batter forms. Mix in the fresh blueberries.
Stir the ingredients for the walnut cinnamon swirl topping in a small bowl until well-combined.
Pour 1/2 to 2/3 of the cake batter into the prepared cake pan and smooth into an even layer. Evenly spread 1/2 to 2/3 of the walnut topping mixture on top of the cake batter and use a knife to swirl it into the batter.
Repeat for remaining cake batter and walnut topping.
Cover the coffee cake with foil and bake on the center rack of the preheated oven for 30 minutes. Remove the foil then bake for another 15 to 20 minutes, or until the cake has set up in the center and the edges are golden-brown. Insert a thermometer into the center of the cake to check for doneness. It is ready if the internal temperature is 190 degrees or higher.
Remove cake from the oven and allow it to cool all the way to room temperature (at least 30 minutes). Cut into slices and serve alongside a mug of coffee or tea.