Cut each sprout in half and take out hte touch outer leaves.
Dice bacon into small bits.
Cut onion into pieces that are roughly the same size as the sprouts.
Take a quart Ziploc bag (or a bowl) and mix all of the ingredients together.
Line a baking sheet with foil and spread the mixture in an even, single layer.
Bake at 350 for 30-50 minutes, turning half-way through.
You may want to finish up by broiling them to get them properly caramelized. I precooked them ,and when it was time to reheat, I broiled them to get them crispy.
You can cut and mix the veggies and bacon ahead of time and put the ziploc back in the fridge. This way you can prep the veggies and pour them in a pan when it's time to start dinner.