Slow Cooker Sausage and Lentil Soup
Crispy bacon, browned Italian sausage, and earthy green lentils slow-cooked in a smoky tomato broth with aromatic vegetables. A deeply satisfying bowlful that practically makes itself.
- 6 strips bacon, cut into small pieces
- 16 ounces Italian sausage
- 1 medium onion, finely chopped
- 2 sticks celery, finely chopped
- 1 medium red bell pepper, finely chopped
- 4 cloves garlic, minced
- 6 cups chicken broth
- 1 can (15 oz) tomato sauce
- 1½ cups dry green or brown lentils
- ½ teaspoon dried oregano
- ¼ teaspoon crushed red pepper flakes, or to taste
- Salt & pepper to taste
- Set a large skillet over medium-high heat and fry the bacon pieces until they are fully crisp, which will take around 10 minutes. Transfer them to a plate lined with paper towels and leave all the rendered fat in the pan — this is the flavour base for everything that follows.
- Add the Italian sausage to the same skillet and cook over medium-high heat for 7 to 8 minutes, breaking it apart into small crumbles with a wooden spoon as it browns. You want good colour on the meat, not just grey. Transfer the browned sausage to the plate with the bacon.
- Pour off all but 1 to 2 tablespoons of the fat remaining in the skillet. Add the onion, celery, and red bell pepper and sauté over medium heat, stirring occasionally, for 5 to 7 minutes until the vegetables have softened and picked up a little golden colour at the edges. This step builds the aromatic backbone of the soup — don't rush it.
- Add the minced garlic to the skillet and stir constantly for about 30 seconds until fragrant. Garlic burns quickly in a hot pan, so keep it moving and pull it off the heat the moment the raw smell transforms into something sweet and toasty. Tip the entire skillet mixture into the slow cooker.
- Add the reserved bacon and browned sausage to the slow cooker, followed by the chicken broth, tomato sauce, lentils, dried oregano, and crushed red pepper flakes. Stir everything together to combine, then cover and cook on high for 3 to 4 hours or on low for 6 to 8 hours. The lentils should be completely tender and beginning to break down slightly into the broth.
- Taste the finished soup and season with salt and pepper as needed, keeping in mind that the bacon and sausage both carry salt. If you prefer a thicker, creamier texture, use an immersion blender to partially blend the soup — a few passes around the pot is enough to give it body while keeping plenty of whole lentils and vegetable pieces intact. Ladle into bowls and serve immediately.
Chef’s Note: The technique of browning the bacon and sausage before anything goes into the slow cooker is what separates this soup from a thin, muddy broth. Rendering the bacon first gives you the fat to cook everything else in, and browning the sausage in that same fat builds a layer of deep savouriness that no amount of slow cooking alone can replicate. The Maillard reaction happening in the skillet is doing real work here — don’t shortcut it by dumping everything raw into the pot. If you’re using whole sausages rather than bulk sausage meat, simply split the casings and squeeze the meat out before frying.
This soup improves significantly overnight as the lentils absorb the broth and the smoky, spiced flavours deepen. It keeps well in the refrigerator for up to four days and freezes beautifully for up to three months — making it an excellent candidate for batch cooking. When reheating, you may need to loosen it with a splash of broth or water, as the lentils continue to swell. For a stovetop version, complete the sautéing steps in a large Dutch oven or heavy soup pot, then add the remaining ingredients and simmer covered on low heat for about an hour, or until the lentils are fully tender.
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