Make the streusel topping: In a medium bowl, combine the almond and coconut flours, sugar, cinnamon, and coconut oil. Using the back of a fork, work the coconut oil into the dry ingredients until broken down into pea-sized pieces. Stir in the maple syrup and pecans. The streusel should look like wet sand with some larger chunks. Set aside.
Make the cake: In a large bowl, whisk together the yogurt, eggs, vanilla, coconut oil, maple syrup, and apple cider vinegar until smooth.
In a medium bowl, stir together the almond flour, coconut flour, cinnamon, nutmeg, baking soda, and salt.
Toss the blueberries with 2 tablespoons of the flour mixture and set aside.
Using a rubber spatula, incorporate the dry ingredients into the wet ingredients, stirring until any dry clumps are gone and the batter is smooth. Fold in the blueberries.
Cut a 4×15 inch (10×38 cm) piece of parchment paper. Reserve the excess parchment. Grease an 8×4 inch (20×10 cm) loaf pan with coconut oil, then line the pan with the piece of parchment paper so it hangs over the sides. Use the reserved scrap of parchment paper to lay across the pan in the opposite direction.
Pour the batter into the prepared loaf pan and smooth the top. Sprinkle the streusel topping evenly over the batter.
Bake for 45-50 minutes, until the top is golden brown and a toothpick inserted in the center comes out clean. If the top is getting dark too quickly, tent with foil for the final 15 minutes of cooking.
Let the coffee cake cool for 15 minutes, then use the parchment paper to carefully lift the cake out of the pan. Let cool for another 15 minutes before slicing.