Cook the pasta until al dente as indicated on the package.
Finely dice the onion and garlic, clean the leek and cut into fine strips. Dice the boiled ham.
Heat 2 tablespoons of oil in a saucepan and sauté onion and garlic in it. Add the leek and ham and sauté briefly. Finally add the red lentils and the broth. With the lid closed, simmer for 5-8 minutes until the lentils are cooked (they should never fall apart).
Fold in the drained pasta.
Mix the remaining oil with the balsamic vinegar and season with salt, pepper and a little sugar. Pour over the pasta and mix everything well.