Start by making the stuffing for your squash. Bring a medium-sized pot to medium-high heat. Add in the butter, and let that melt. Toss in your lentils, rice, and barley and give this a good stir. Cook, and continue to stir for a few minutes. Next add the carrots and onion. Season with salt and pepper, then toss in the red chard. Stir, then add in your chicken stock. Give another good stir, then simmer for 30 minutes. After 30 minutes, remove from the hit, and partially open the lid to prevent it from over cooking.
Preheat your oven to 425 degrees.
Once you have sliced your squash, take a knife and make score marks, about 1/2 inch down. Rub the skin with the canola oil, and place the squash onto a baking sheet, skin side up. Roast in the oven for 45 minutes.
During this time, heat another large skillet on medium-high heat. Add the Boerewors sausage to the preheated skillet, and cook until the sausage is fully cooked. Make sure you crumble it along the way. Add the lentil mixture to the sausage, and give a good toss and stir.
When the squash are done cooking, let them cool until you can handle the squash, about 10 minutes. Carefully turn the squash over, and use a spoon to remove the cooked squash, leaving the shell in tack.
Add the squash to the lentil and sausage mixture, mixing well, then add this back into the cavity of the squash. Place the stuffed squash back into a preheated 425 degree oven and cook for another 15 minutes, or until the sausage mixture gets nice an crunchy.
Plate and serve.