Heat the oven to 425 degrees.
Grease a deep roasting pan with oil.
Put the bacon in the roasting pan and put it into the oven and let it cook for 3 or 4 minutes.
Put the vegetables into the roasting pan and stir into the bacon and bacon fat. (If you are using broccoli or onions, leeks or garlic, don't add those for another 20 minutes or so. They cook a lot faster than, say, carrots and cauliflour.)
Stir in some olive oil if needed so that everything is lightly coated with oil. (May not need much if there is a lot of bacon fat.)
Roast, stirring every 10 minutes or so, until the vegetables are tender and lightly browned; takes 45 to 60 minutes. (Of course, be careful not to taste it till the bacon is done.)
Remove the pan from the oven. (Above photo shows the vegetables at this stage.)
You can stop here if you want and just serve as roasted vegetables (yum), or, to make stew continue to next step.
Transfer the contents of the pan to a large pot and put on medium heat. Be sure to get all the scrapings from the pan. (If your pan can be used on the stovetop, you won't need to transfer.)
Stir in the sage and white wine and broth and (optional) tomato paste.
Cook until the vegetables break apart a little and the broth is well flavored, 10 to 25 minutes.
Taste and add salt/pepper if desired.
Serve with romano or parmesan cheese and (optional) toast.