
Preheat the oven to 350°F (170°C). In a mixing bowl, whisk together the all-purpose flour, salt, ground cinnamon, and baking powder until evenly combined.



In a blender, combine the vegetable oil, brown sugar, mayonnaise, egg, and vanilla. Blend until the mixture looks thick, smooth, and glossy.



Pour the blended wet mixture into the dry ingredients. Stir with a spatula until no dry flour remains and the batter is smooth, but avoid overmixing.


Lightly grease a mini Bundt pan, making sure to coat the center tube and all the grooves. Spoon or pour the batter into the pan and smooth the top. If using a silicone Bundt pan, place it on a sturdy baking sheet for support.



Bake for 30 to 35 minutes, or until the cake is set and a toothpick inserted near the center comes out clean. While the cake bakes, combine the crumb topping ingredients in a small bowl and gently rub them together until coarse crumbs form.



Let the cake cool in the pan for 10 minutes, then carefully loosen the edges and invert it onto a baking sheet or oven-safe plate. Sprinkle the crumb topping over the cake, then return it to a hot oven for 2 to 3 minutes, just until the crumbs lightly set. Serve warm or at room temperature.







