Preheat oven to 325 degrees F (165 degrees C). Grease one 8-inch cake pan and dust with almond flour.
Whisk almond flour, honey, walnuts, cocoa powder, eggs, coconut oil, and vanilla extract together in a large bowl. Pour into prepared pan and smooth top.
Bake in the preheated oven until the center is set and edges pull away from sides of the pan, 20 to 25 minutes. A toothpick inserted into the center should be clean or have a few moist crumbs attached.
