Place lentils in a large pot and cover with water. Bring to a boil, and
continue cooking for just 5 minutes. Drain and set lentils aside.
Heat the vegetable oil in a heavy large saucepan over medium heat.
Add the onions, after 5 minutes add the carrots, and after another 5
add the red peppers with a pinch of salt and pepper. Cook together
for an additional 10 minutes.
Add to the saucepan the remaining 3 tablespoons vegetable oil with
the salt, pepper, the crushed chillies, 2 bay leaf and the beef, and
cook until the beef starts to brown.
Incorporate the canned crushed tomatoes (save 1 cup to add during
the final cooking) and the canned plum tomatoes, diced (if using).
Then add the lentils and bring to boil. Reduce heat to medium-low,
cover and simmer until lentils are tender, about 30-40 minutes.
Check pot after 20 minutes, and add the reserved crushed tomato
liquid if needed. Do not stir.
When lentils are tender, add the kosher merguez sausage. Cook until
lentils are soft, an additional 10-15 minutes.
To add more flavour, incorporate one garlic clove and an extra kosher merguez sausage.
If the stew gets dry during the cooking, add some water instead of more canned tomato.