Preheat the oven to 350 F (180 C) and line a standard-sized loaf pan (approx. 8.5 x 4 inches) with parchment paper.
Mash the banana well in a small bowl until completely smooth. Finely grate the carrot.
In a large bowl, whisk together all the dry ingredients: flour, sugar, baking powder, baking soda, cinnamon, nutmeg and pinch of salt.
1 1/3 cup spelt flour or all purpose flour, 1 teaspoon baking soda, 1 teaspoon baking powder, 2 teaspoons cinnamon, 1/4 teaspoon nutmeg, 1/8 tsp salt, 1/2 cup + 2 tablespoons coconut sugar
Now add all the wet ingredients, banana puree, milk, vanilla and the apple cider vinegar and mix well until all the flour is wetted.
1/2 cup mashed banana, 3/4 cup plant-based milk, 2 teaspoons vanilla, 1 teaspoon apple cider vinegar
Fold in the grated carrots and the chopped walnuts and mix until combined.
1/3 cup chopped walnuts or pecans, 1 cup finely grated carrot
Bake for 25 to 30 minutes or until a toothpick inserted comes out clean.
Let cake cool completely in the pan before slicing and serving.