1 onion, chopped
a few cloves of garlic, minced
aromatic vegetables (carrots, celery, leeks, or whatever else you have on hand), chopped
olive oil or butter
1 32 oz. can tomatoes, with their juice
2 cups good chicken stock, or water
½ cup red lentils
salt to taste
large handful minced fresh rosemary (optional)
greens, roughly chopped (kale is a favorite here)
Heat some olive oil (scant ¼ cup?) in a soup pot. Add the onions, salt to taste, and cook over medium heat until softened but not browned. Add the garlic, rosemary and aromatic veg (if using), and allow the garlic to soften as well. Add tomatoes, lentils, and broth or water, salting to taste. Bring to a simmer and then turn heat to medium low (or whatever heat the soup simmers gently at on your stove). Simmer, partially covered, until the lentils are creamy and falling apart, (at least 1 1/2 hours for us). Do remember to stir the soup occasionally, though it doesn't need much attention if the heat is low enough. We often putter around the garden or go for a short walk after we get this going IF the heat is right. We've also put this in a 300 degree oven and gone for a longer walk: we call this the poor man's crockpot.
When the lentils are completely soft, check the seasonings and adjust as necessary. Puree with an immersion blender, or use a food mill or regular blender. If adding greens, return the soup to your saucepan and toss the chopped or torn greens on top. Turn up the heat to medium and steam the greens.
Sometimes we swirl a dollop of pesto or green goddess into each bowl for variety. Delicious with salmon broiled in herbed and oiled breadcrumbs and a salad of some kind.