In a large pot or Dutch oven, heat the oil until hot but not smoking over medium heat

Add the onion and minced garlic and cook, stirring frequently, until the onion has softened, about 5 minutes

Stir in the carrots and sweet potatoes and cook until the carrots and potatoes are softened, about 5 minutes

Add the tomato, stirring to coat

Stir in the split peas, 5 cups of water, the thyme, salt and pepper

Bring to a boil, reduce to a simmer, and cover

Cook, stirring occasionally, until the split peas are tender, about 35 minutes. Meanwhile, preheat the oven to 400F

Rub both sides of the bread with the cut sides of the halved garlic; discard the garlic

Cut the bread into 1-inch pieces for croutons

Place the bread on a baking sheet and bake for 5 minutes, or until lightly crisped

Set aside. Transfer the split pea mixture to a food processor and puree until smooth, about 1 minute

Return the puree to the pot, stir in the \turkey sausage and lemon juice, and cook, uncovered, just until the turkey sausage is heated through, about 2 minutes longer

Ladle the soup into bowls, sprinkle the croutons on top, and serve.