Chop finely the onion and the garlic clove and brown it in a couple of tablespoons of olive oil. When it starts to change its colour add the lentils, the sage, salt and pepper. Gently stir it for a couple of minutes and then add the water. Bring to boil and then reduce the heat. They will need about 30 minutes to be cooked but still a bit firm to the bite.
Gently boil or steam the king prawns for not more than 5 minutes.
Heat a frying pan without using any oil. Place the slices of pancetta and gently keep turning them until they are cooked but still soft.