Add 1 diced medium yellow onion and 2 diced medium celery stalks to the pot. Cook, stirring occasionally, until the onion is softened, about 5 minutes. Stir in 2 pounds peeled and diced sweet potatoes, 3 minced garlic cloves, 1 3/4 teaspoons kosher salt, 1 teaspoon dried thyme if using, 1 teaspoon smoked paprika, and 1/2 teaspoon black pepper. Cook until the garlic is fragrant, about 3 minutes.
