Preheat oven to 425F. Slice sausage into 1 inch thick slices on a diagonal. Slice peppers into thin strips, slice yellow onion into thin slices, and cut cherry tomatoes in half.
Pour all ingredients into a mixing bowl. Mix tomato paste, balsamic vinegar, olive oil, salt, pepper, oregano, and garlic powder in a small bowl. Pour over other ingredients and toss to combine.
Spread into an even layer on a greased sheet pan - for this recipe I prefer not to use parchment paper to help the ingredients crisp a little. Bake at 425F for 30 minutes - toss once halfway through.
If you want to brown the ingredients slightly, increase the heat to a broil and broil for 2-3 minutes before removing from the oven.
Top with grated parmesan cheese and fresh basil or oregano. Serve on its on or over pasta or in rolls.
Notes
Store in an air tight container in the fridge for up to 4 days.