Preheat the oven to 350 degrees Fahrenheit and line a 8” x 8” square baking pan with parchment paper.

In a small bowl or measuring cup, stir together the ingredients for the nutty streusel topping until well-combined. Set aside until ready to use.

Whisk together the melted coconut oil, eggs, and pure vanilla extract in a large bowl until creamy (wet ingredients).

In a separate medium bowl, stir together the gluten-free all-purpose flour, sugar, baking powder, and sea salt (dry ingredients).

Pour the flour mixture into the bowl with the wet ingredients and stir until completely combined and a thick, oily dough forms.

Gently stir in the blueberries.

Transfer half of the coffee cake batter to the parchment lined pan and gently press it into an even layer (I use a fork or my hands for this step).

Sprinkle half of the nutty streusel topping over the batter.

Transfer the remaining cake batter on top and press it into an even layer (I find this is easiest to do with my hands). Similarly, sprinkle the rest of the remaining streusel topping on top.

Bake on the center rack of the preheated oven for 30 minutes. Remove the coffee cake from the oven, cover it in foil, and bake for another 15 to 20 minutes, until the cake feels firm when gently poked and tests clean.

Remove the coffee cake from the oven and allow it to cool to room temperature before slicing and serving. Note: slicing the cake before it cools will guarantee a lot of crumbling.