Roasted Root Vegetable and Ricotta Manicotti

Name: Roasted Root Vegetable and Ricotta Manicotti
Ingredients: 8 manicotti shells; 1/4 cup light ricotta; 1 egg yolk; 2 tbsp shredded part-skim mozzarella cheese; 2 tbsp finely chopped fresh chives (divided); 1 tbsp finely chopped toasted walnuts; 3 cups chopped mixed root vegetables (such as, carrots, parsnips, celery root, golden beets, turnip and/or rutabaga); 1 tbsp finely chopped fresh thyme; 2 tsp finely chopped fresh rosemary; 1 tsp olive oil; 2 cloves garlic (minced); Pinch each salt and pepper