Heat the olive oil in a cast iron or soup pot over a medium heat. Once it’s hot add the pancetta or bacon and start to brown and crisp the bacon in a splash of olive oil. While the bacon is cooking, use that time to chop your vegetables.
Dice the carrots, celery and onion into bite size pieces. Once the bacon is brown and crispy, use a slotted spoon to remove the lardons to a small bowl. Keep about 2 tablespoons of the bacon fat and pour the rest away. We're using this rich and salty bacon fat to soften the vegetables. Add the vegetables to the pot and start to soften.
Once the vegetables are beginning to soften add in some fresh rosemary and the dried herbs. Give them all a good stir.
Next up add in the lentils and the sliced mini potatoes. Give them a stir to coat them in the bacon fat and mix in with the vegetables.
Add in the vegetable stock or you can use water. Bring this up to a boil, then turn down to a gentle simmer. Simmer for about 20 minutes, until the lentils are tender.
Place about ⅓ of the soup in a blender and blend until creamy and smooth. Add this back into the soup pot and give it a good stir. This brings the soup to the next level! It makes it thick and creamy without adding in anything extra.
Add in the lemon juice and spinach and stir well. Add the bacon lardons back the pot. The heat from the soup will wilt the spinach. Don't skip this. The soup is thick and full of vegetables. It needs that little burst of acid to tie it all together! Trust me!