Preheat the oven to 200 degrees Celsius (400 degrees Fahrenheit)
To prep the brussel sprouts, wash them and cut off any of the tough outter leaves. To make sure everything cooks evenly, cut any of the larger brussel sprouts in half.
Place the cubed butternut squash, brussel sprouts, chopped pancetta or bacon and red onion on a large baking sheet.
In a bowl whisk together the olive oil, balsamic, mustard, thyme, salt and pepper and then pour over the veggies on the baking sheet. Place everything in the oven and bake for 35 minutes tossing the veggies half way through baking to ensure they evenly cook.