Preheat oven to 350F. Spray a 9x5-inch loaf pan with cooking spray or grease and flour the pan; set aside.

Peel the sweet potatoes and chop into 1-inch chunks. Microwave with 3 tablespoons water, covered, for 15-17 minutes until very tender; or boil until soft. Mash and let cool.

In a bowl, whisk together mashed sweet potatoes, eggs, oil, buttermilk, and vanilla until well combined.

In a large bowl, whisk together the dry ingredients: flour, sugar, brown sugar, baking soda, cinnamon, ginger, nutmeg, allspice, cloves, and salt.

Pour the wet mixture into the dry ingredients and gently fold until just combined, avoiding over-mixing.

Pour batter into prepared loaf pan and bake for 60-70 minutes, or until a toothpick inserted in the center comes out clean. Cover with foil during the last 15 minutes if top is browning too fast.

Allow the bread to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before slicing.