This sausage and lentil soup is the kind of dish that became a weeknight staple in my kitchen the moment I perfected the balance of smoky pork, sweet tomato, and earthy lentils. I discovered this combination on a chilly evening when the pantry offered lentils and a package of Italian sausage, and the slow cooker saved the night: minimal babysitting, maximum flavor. The result is a bowl that greets you with a rich aroma, generous chunks of sausage and bacon, and just the right body from the lentils — comforting but not heavy. Friends and family always ask for seconds, and leftovers improve overnight as the flavors marry. I love that this is a social recipe and a practical one. Browning the bacon and sausage in advance gives the final pot a depth many one-pot recipes miss, but most of the hands-on work is front-loaded into a 20-minute stint at the stove. The slow cooker does the rest, softening the lentils into tender morsels and coaxing the tomato and broth into a cohesive, spoonable gravy. Texturally it’s satisfying: a pop of crisp bacon at the finish, meaty sausage pieces, and lentils that hold their shape but give way easily. Taste notes are smoky, tomato-forward, garlicky and gently spiced with oregano and crushed red pepper. It’s the sort of bowl that warms you from the inside out and makes an ordinary evening feel cared for.

Ingredients

• Bacon (6 strips): Use thick-cut if you like a meatier bite and more rendered fat for browning. I often buy center-cut for a good balance; cook until crisp to get a crunchy garnish and deep smoky flavor in the grease.
• Italian sausage (16 ounces): Mild or sweet works well for most families; choose a quality fresh pork sausage with fennel seeds if you like an aromatic note. Remove casings and crumble while browning for even pieces.
• Onion (1 medium): Yellow onion is my preference for its balance of sweetness and savory notes; finely chop so it melts into the base of the soup.
• Celery (2 stalks): Chop finely for texture and classic aromatic support; the celery adds subtle freshness and helps build the sofrito base.
• Red bell pepper (1 medium): Adds sweetness and color; chop small so it softens evenly during the initial sauté.
• Garlic (4 cloves): Minced fresh; don’t substitute powdered here — the fresh garlic brightens the entire pot.
• Chicken broth (6 cups): Use low-sodium if you plan to salt at the end; homemade or a trusted brand like Swanson gives the best results.
• Tomato sauce (15 ounces): One standard can; it contributes tomato body without the chunkiness of diced tomatoes and keeps the broth silky.
• Dry green or brown lentils (1 1/2 cups): No soaking required — these hold their shape well in the slow cooker and provide the stew-like texture.
• Dried oregano (1/2 teaspoon) and crushed red pepper flakes (1/4 teaspoon): Simple dried herbs highlight the Italian sausage; adjust the red pepper for heat.
• Salt and freshly ground black pepper: Add to taste at the end to avoid over-salting if your broth or sausage is salty.

Instructions

Prepare and brown the bacon: Heat a large skillet over medium-high. Add the bacon strips cut into small pieces and fry until crispy, about 8–10 minutes, stirring occasionally so they cook evenly. Transfer the bacon to a paper-towel-lined plate and leave the rendered fat in the skillet; this fat will carry deep flavor into the vegetables and meat. Brown the sausage: In the same skillet, add the Italian sausage (remove casings if needed) and cook over medium-high heat, breaking it into small pieces with a spoon, until browned and no longer pink, about 7–8 minutes. Transfer the browned sausage to the plate with the bacon; a few browned bits on the pan are good — they become flavor for the next step. Sauté the vegetables: Leave 1–2 tablespoons of fat in the skillet. Add the chopped onion, celery and red bell pepper and sauté over medium heat until softened and just starting to caramelize, about 5–7 minutes. Look for translucent edges and a little color; this caramelization gives the final pot depth. Stir in the minced garlic and cook for 20–30 seconds until fragrant — avoid burning it. Combine in the slow cooker: Transfer the sautéed vegetables to the slow cooker, then add the cooked bacon and sausage. Pour in 6 cups of chicken broth, the 15-ounce can of tomato sauce, and the 1 1/2 cups of dry lentils. Stir in 1/2 teaspoon dried oregano and 1/4 teaspoon crushed red pepper flakes. Give everything a good stir so the lentils are submerged. Cook low and slow: Cover and cook on HIGH for 3–4 hours or LOW for 6–8 hours. I usually set it on LOW and let it go while I run errands; lentils will become tender but maintain some bite. If the lentils or broth seem too thick near the end, stir in an extra 1/2 to 1 cup of broth or water. Finish and season: Taste and season with salt and freshly ground black pepper to your preference. If you prefer a thicker, creamier body, use an immersion blender to pulse a portion of the soup right in the pot until you reach the desired texture. Serve hot with chopped parsley and reserved crispy bacon on top for contrast.

Storage Tips

Cool the soup at room temperature no longer than two hours, then transfer to airtight containers. Refrigerate for up to 3–4 days. For longer storage, freeze in individual portions in freezer-safe containers for up to 3 months. When reheating, thaw overnight in the refrigerator and reheat on low in a saucepan with an extra splash of broth to revive the texture; for microwave reheating, cover and stir halfway through to ensure even warming. Crisp bacon garnish separately in a skillet and add at serving time to preserve crunch.

Ingredient Substitutions

If you want to lighten the pork element, substitute half the sausage with ground turkey and add a teaspoon of fennel seed to mimic the aromatic character of Italian sausage. Swap chicken broth for vegetable broth to make a pescatarian-friendly version (omit the sausage and bacon and replace with smoked tofu or roasted mushrooms for umami). Red lentils will break down and create a thicker, stew-like consistency if preferred, but adjust the cook time down slightly to avoid disintegrating them.

Serving Suggestions

Serve with a wedge of crusty bread or garlic toast to sop up the broth, and a simple green salad dressed with lemon vinaigrette to cut the richness. A drizzle of good olive oil and a scatter of chopped parsley or grated Parmesan (optional) elevates each bowl. For a heartier meal, spoon the soup over creamy polenta or alongside roasted root vegetables in colder months.

Cultural Background

Legume-and-pork combinations are common across Mediterranean and southern European cuisines: lentils provide inexpensive, nutritious bulk while cured or fresh pork lends depth. This version skews Italian-American thanks to the use of Italian sausage and oregano, but it’s rooted in the global tradition of simple, slow-simmered stews built on humble pantry staples.

Seasonal Adaptations

In winter, boost the recipe with kale or chopped Swiss chard stirred in 20–30 minutes before the end of cooking for color and nutrition. In spring or summer, skip the slow cooker and simmer on the stovetop for 40–50 minutes to keep the broth brighter and add fresh basil at the end. For holiday gatherings, finish with a spoonful of browned butter and sage for a festive twist.

Meal Prep Tips

Make a double batch and freeze individual portions for quick lunches. When packing for work lunches, keep the bacon garnish separate and add fresh lemon wedges to brighten the soup before eating. Use wide, shallow containers when refrigerating to speed cooling and reduce bacterial growth.

There is comfort in a simple pot that feeds a family, salvages a busy weeknight, or becomes the unexpected highlight of a casual gathering. This slow-cooker sausage and lentil soup does all of that for me — reliable, forgiving, and delicious. I hope it earns a spot in your rotation as it did in mine.