Preheat the Oven: Preheat your oven to 350°F (175°C) and grease an 8-inch square baking dish or line it with parchment paper.
Prepare the Cake Batter: In a large mixing bowl, whisk together the almond flour, coconut flour, coconut sugar, baking powder, baking soda, sea salt, and cinnamon. In a separate bowl, whisk the eggs, almond milk, melted coconut oil, and vanilla extract. Combine the wet and dry ingredients until smooth.
Make the Streusel Topping: In a small bowl, mix almond flour, coconut sugar, cinnamon, melted coconut oil, and sea salt until crumbly.
Assemble the Cake: Pour the batter into the prepared baking dish and spread evenly. Sprinkle the streusel topping generously over the batter.
Bake: Bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean. Let the cake cool slightly before slicing and serving.