"Many people don't know that the crock inside a slow cooker is ovenproof and you can transfer a dish like lasagna into the oven (up to 400°F) for 10 minutes to brown the top," says Golino. Just be sure the pot is hot, to avoid drastic temperature changes that can cause it to crack.
- 1 medium onion, quartered
- 1 cup fresh basil leaves
- 1 Tbs. dried oregano
- 2 cloves garlic, peeled, plus 1 clove minced (1 tsp.), divided
- 1 8-oz. pkg. tempeh, cut into chunks
- 1 28-oz. can chopped fire-roasted tomatoes
- 2 Tbs. olive oil, plus more for oiling slow cooker
- 1 tsp. salt
- ½ tsp. ground black pepper
- 2 10-oz. pkgs. frozen spinach, thawed and drained
- 8 oven-ready lasagna noodles
- 1 16-oz. jar roasted red peppers, rinsed and drained
- 1 16-oz. container low-fat ricotta cheese, divided
- 1 cup grated Swiss cheese, divided
1. Place onion, basil, oregano, and 2 whole garlic cloves in food processor; pulse 6 times, or until onion and garlic are chopped. Add tempeh, and pulse until tempeh is ground. Add tomatoes, oil, salt, and pepper; pulse until chunky sauce forms.
2. Combine spinach and minced garlic in bowl, and season with salt and pepper.
3. Coat bottom and sides of 4-quart slow cooker with oil. Spread 1 cup tomato sauce over bottom, and cover with layer of lasagna noodles, breaking them in pieces to fit around edges. Spread 3/4 cup spinach mixture over top. Place 1 layer roasted red peppers over spinach, and top with 3/4 cup ricotta. Spread 1 cup tomato sauce over ricotta. Sprinkle with 1/3 cup Swiss cheese. Repeat, layering noodles, spinach, peppers, ricotta, Swiss cheese, and tomato sauce. Top with 1 more layer noodles and remaining spinach, tomato sauce, ricotta, and Swiss cheese.
4. Cook 4 hours on high or 6 hours on low. Let stand uncovered 10 minutes before serving.