Step 1

Add the onion, celery, carrot, garlic, 1 teaspoon salt, lentils, tomatoes, stock and bay leaf to a 6-quart slow cooker, stirring to combine. Do not add the spinach, it will be added at the end.

Step 2

Cover and cook on high for 4-6 hours or on low for 6-8 hours, or until the veggies and lentils are soft.

Step 3

Remove the lid, remove the bay leaf, add the vinegar, and stir to combine. Add an additional 1-2 cups of stock to thin the soup if necessary. Taste and add the remaining 1 teaspoon salt, plus additional vinegar if desired.

Step 4

Using an immersion blender, blend for 5-10 seconds. Alternatively, carefully, remove ½ to 1 cup of cooked soup to a blender. Cover, blend on high, then add back to the soup, stirring to combine. Note: Blending for just a few seconds will add a creaminess to the soup, while leaving the texture of most of the lentils and vegetables intact.

Step 5

Add the spinach, and stir to combine. Serve with a generous drizzle of olive oil, and any other toppings you like.

Step 6

Set a 6-quart pressure cooker to saute mode for 8 minutes. Add 1 tablespoon olive oil, onion, a pinch of salt, and cook, stirring occasionally, until the onions are soft.

Step 7

Cancel the saute function. Add the celery, carrot, garlic, 1 teaspoon salt, lentils, tomatoes, stock, and bay leaf, stirring to combine.

Step 8

Secure the lid, select the manual setting, and set it to high pressure for 15 minutes.

Step 9

When the pressure cooker timer is done, allow to naturally release for 15 minutes.

Step 10

Follow remaining slow cooker steps 3-5.

Step 11

Heat 1 tablespoon olive oil over medium high heat in a large Dutch oven. Add the onion and a pinch of salt, stirring to combine. Cook until the onions soften, about 8 minutes, stirring occasionally.

Step 12

Add the celery, carrot, garlic, and 1 teaspoon salt, stirring to combine. Cook for an additional 2 minutes, stirring occasionally.

Step 13

Add the lentils, tomatoes, bay leaf, and stock, stirring to combine. Cover, bring to a boil, then reduce to a simmer.

Step 14

Cook, covered, until the lentils are soft, about 35-45 minutes, stirring occasionally.

Step 15

Follow remaining slow cooker steps 3-5.