Pork Tenderloin in a Sweet Citrus Sauce without vinegar

2 lbs pork tenderloin 3 large sweet potatoes , peeled and cubed 2 firm ripe bosc pears , not peeled and cut into 6 wedges 1 medium Spanish onion , sliced thin[...]

1/4 cup ketchup 1/4 cup brown sugar 1 tablespoon soy sauce , low sodium 1/2 teaspoon fresh gingerroot, grated 1 garlic clove , chopped 1/8 teaspoon dry[...]

1/2 teaspoon salt 1/4 teaspoon ground cinnamon 1/4 teaspoon ground cardamom 1/8 teaspoon black pepper 1 large sweet potato , in 1-inch slices (peeled or not)[...]