Slice one small onion and sweat in a little olive oil for a few minutes (You can also use coconut oil; I have been told this oil increases your metabolism.... do we believe? I'm not so sure...). Add one teaspoon of smoked paprika, 1/4 tsp cayenne pepper, 2 cloves of crushed garlic and a sprig or two of thyme (dried is fine). When the onions are soft add one and a half cups of red lentils and 750ml of veg stock (or beef if you are feeling less healthy). Cover with a lid and simmer for 10-15 mins or until the lentils are cooked.
Finish with a good squeeze of lemon juice and some salt to taste. Top with freshly chopped tomatoes and a sprinkle of parsley.
Used as a base this soup recipe makes a really good fish stew: Add an extra half to a whole cup of lentils and throw in some cubes of chorizo while frying the onions. When the lentils are nearly cooked add some chunks of white fish and a handful of prawns. Simmer for an extra 5 minutes or so until the fish is done.