Hidden Mushroom and Lentil Bolognese with Spaghetti

By Lauren Mitchell, Test Kitchen Director · Reviewed by AislePrompt Editorial · Published 2026-06-19 · Updated 2026-06-19

A hearty vegetarian Bolognese sauce made with finely chopped mushrooms and lentils, simmered in a rich tomato base and served over spaghetti. This italian-inspired pasta (vegetarian) ready in about 65 minutes pairs olive oil, medium, finely chopped yellow onion, medium, finely chopped carrot for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 420 calories and feeds 4, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Ingredients

• 2 tbsp olive oil
• 1 medium, finely chopped yellow onion
• 1 medium, finely chopped carrot
• 1, finely chopped celery stalk
• 3 cloves, minced garlic cloves
• 8 oz, finely chopped cremini mushrooms
• 3/4 cup, rinsed dry brown lentils
• 1 can (28 oz) crushed tomatoes
• 2 cups vegetable broth
• 1 tsp dried oregano
• 1/4 tsp red pepper flakes
• 1 1/2 tsp, divided salt
• 1/2 tsp, divided black pepper
• 12 oz spaghetti
• 1/4 cup, chopped (optional) fresh basil leaves

Instructions

1. Step 1: Heat 2 tbsp olive oil in a large pot over medium heat. Add 1 medium finely chopped onion, 1 medium finely chopped carrot, and 1 finely chopped celery stalk. Sauté for 6-7 minutes until softened and fragrant.
2. Step 2: Add 3 minced garlic cloves and 8 oz finely chopped cremini mushrooms to the pot. Cook for 5 minutes until mushrooms release moisture and begin to brown.
3. Step 3: Stir in 3/4 cup rinsed dry brown lentils, 1 tsp dried oregano, 1/4 tsp red pepper flakes, 1 tsp salt, and 1/4 tsp black pepper. Pour in 1 can (28 oz) crushed tomatoes and 2 cups vegetable broth.
4. Step 4: Bring the sauce to a boil, then reduce heat to low and simmer uncovered for 35-40 minutes, stirring occasionally, until lentils are tender and sauce thickens.
5. Step 5: Meanwhile, bring a large pot of salted water to a boil. Add 12 oz spaghetti and cook according to package instructions until al dente. Drain and reserve 1/2 cup pasta water.
6. Step 6: Taste the sauce and adjust seasoning with 1/2 tsp salt and 1/4 tsp black pepper if needed. Add reserved pasta water 2 tbsp at a time to loosen sauce if too thick.
7. Step 7: Toss drained spaghetti with the mushroom lentil Bolognese sauce. Garnish with 1/4 cup chopped fresh basil leaves if desired before serving.