Line the full-size baking sheet with parchment paper. Preheat the oven to 425 Fahrenheit.
Cut the onions into equal thin strips and scatter them onto the parchment-lined baking sheet. Cut the sausage into approximately one-quarter slices. Then clean and cut the garlic into thin pieces. Wash, remove the seed, and cut the bell peppers into thin strips. Wash and cut the baby potatoes in half.
Spread the sausage, garlic, bell peppers strips, and baby potatoes onto the baking sheet. Pour the four tablespoons of canola oil onto the sausage and veggies. Then, sprinkle the seasoning (old bay seasoning, thyme, consommé seasoning, ¼ teaspoon salt, and ⅛ teaspoon grounded black pepper). Toss around the veggies until evenly coated.
Put the baking sheet into the oven for 15 minutes. While the sausage and veggies are roasting, clean the brussels sprouts. Wash them and remove any loose leaves. Then, cut the bottom piece and then cut the brussels sprouts into halves. Set them aside in the bowl. Sprinkle with ¼ teaspoon salt and a pinch of black pepper. Then drizzle the 1 tablespoon canola oil and mix until evenly coated. Finally, wash the cherry tomatoes and cut them into halves.
Remove the baking sheet from the oven and toss the sausage and veggies to ensure nothing sticks to the pan. Arrange the brussels sprouts onto the baking sheet, with their flat sides down. Make sure to place them whenever you have room around other veggies (you want to put them onto the baking sheet directly if possible). Then scatter the halved cherry tomatoes onto the baking sheet. Return the baking sheet to the oven for another 25-28 minutes.
Remove the baking sheet from the oven and poke the baby potatoes with the fork. If they are tender, your meal is done baking. If not, return to the oven for another 3 minutes. Serve immediately.