Preheat the Oven: Begin by preheating your oven to 375°F (190°C).
Toast couscous: On medium heat in a skillet toast the couscous until light golden. Careful not to burn! This will take about 5 minutes.
Blanch Bell peppers: In a large pot add water deep enough to cover half of a bell pepper. Cut your bell peppers in half and then core out the seeds and all the extra flesh inside. Put about 3-4 peppers into your boiling pot of water and make sure they are submerged. Let boil for about 5-7 minutes, repeat with all bell pepper half.
Brown meat and caramelized vegetables: Dice 1 onion, shred 2 carrots and dice ½ a bell pepper. In a large skillet drizzle some oil on the bottom and heat to medium heat. Start by browning the 1 lb of Italian sausage until browned (it doesn't need to be fully cooked through). Set aside and in the same pot start sautéing vegetables. Start with diced onions, then add in carrots and bell pepper. Once caramelized you can season with salt and pepper to taste keep in mind that the Italian sausage had seasonings already in it.
Make the filling: Into the same large pot add in the browned meat and toasted couscous. Then make a well in the center and add ½ cup of tomato sauce wait till it comes to a simmer. Mix the tomato sauce together with the rest of the ingredients and then pour in the 2 cups of broth. Cover the pan with a lid and let it simmer for about 10 minutes until the water has cooked off and the pasta in al dente.
Fill the peppers: Once the filling is ready do a taste test and adjust the seasoning to your preference. Be careful to not over salt ahead of time because the Italian sausage has a lot of flavor as well as the tomato sauce and broth. Let the filling slightly cool for about 5-10 minutes so it will be easier to fill your bell peppers without it being piping hot. Fill each pepper and as you fill press in the filling with the back of your spoon and fill with a slight mound on top.
Make the sauce and Bake the couscous stuffed peppers: In an oven-safe casserole dish arrange your peppers to fit snugly. This will help the filling not pour out of the bell pepper shells.
To make the sauce I use the same pan, and wipe out any extra filling remaining. Then dice up another onion, 2 carrots, and the other half of the bell pepper. Again sautée all the vegetables starting with the onions and later add ½ cup of tomato sauce and 2 cups of broth. Let the sauce come to a simmer then spoon sauce first over each stuffed pepper and then pour the remaining sauce into the bottom, through the cracks.
Sprinkle the top with ¼ cup of feta cheese crumbles. Then cover with foil and bake in a preheated oven at 350F for 40-45 minutes.