Heat a frying pan or Dutch oven large enough to hold all the venison meat over medium high heat. When the pan is hot enough to sizzle water, add the butter and oil and then the venison. Sauté until the meat is well browned, being sure to stir occasionally so the meat doesn't burn. This should take about 5 minutes.
Reduce the heat to medium and add the onions, garlic, bacon and all the mushrooms. Cook for about 10 minutes again being sure to stir frequently. Mushrooms throw off a lot of liquid so when the vegetables begin to brown and all the liquids have evaporated; you are ready to transfer the meat and veggies to a large bowl.
If there is an accumulation of fat left in the pan, get rid of it. (I didn't find much fat at this point). Deglaze the pan with the red wine and use a wooden spoon or spatula to scrape up any brown bits (fond) from the bottom of the pan.
Add the meat and vegetables back to the pan.
Add the sage, paprika, fresh thyme and bay leaf and bring to a boil over high heat. Immediately reduce the heat to a low, cover and simmer for about an hour or until the venison is fully cooked and tender.
Before serving, remove the thyme sprigs and bay leaf from the pan.
I didn't find the need to add a starch to thicken the ragout (liquids) but if you do, just whisk together the arrowroot or cornstarch with ¼ cup of red wine to prepare a thickener. Add it to the pan and simmer until the ragout thickens to your likening.
Taste and season with salt and pepper.
We served it over noodles but you could serve it on rice or potatoes.
Venison is extremely lean so the bacon is there to add a little fat.