In a large bowl, whisk together the wet ingredients–sweet potato, eggs, buttermilk, butter and vanilla.
Add flour, brown sugar, baking powder, spices and salt. Mix until combined (don’t over-mix). Set aside to rest while waffle iron preheats.
Spray the waffle iron with nonstick spray, then heat waffle iron according to the manufacturer’s instructions.
Use a ladle to transfer batter to hot waffle iron (about ⅓ cup for an 8-inch round iron). Close and cook until golden brown, about 2 to 3 minutes (time varies for Belgian waffle iron vs regular iron). Waffles are done cooking when steam starts to dissipate.
Remove waffle from iron and immediately serve with a dollop of whipped cream, chopped pecans and maple syrup.