Then, in a Dutch oven or large stock pot sauté the 1/2" pieces of thick-cut bacon until all fat is rendered and the bacon is slightly crispy.
Once the bacon is done cooking, remove it from the Dutch Oven and place it in a separate bowl. (I like to use a large Pyrex measuring cup or any bowl with a handle.)
Then, salt both sides of the chicken thighs.
Next, sear and brown both sides of the chicken things in the rendered bacon fat. You will need to do this in at least two batches, I recommend no more than four thighs in the pot at a time. Once the thighs have been browned on each side remove the chicken thighs from the Dutch Oven. Place the chicken thighs in the same bowl that you put the cooked bacon in.
Remove all but 2 tbsp of the fat from the cooked bacon and chicken from the Dutch oven.
Now, add the 8 ounces (3 ½ cups or 225 grams) of the mushrooms that were sliced. (The other 6 ounces of mushrooms are reserved for the mushroom skulls.) Add salt and let the mushrooms cook for 2-4 minutes.
Once the mushrooms have been caramelized and cooked down, add 2 tbsp of butter.
Next, add the onions and salt the onions. Sauté the onions. As the onions sauté, they will produce a lot of liquid. Use that liquid to deglaze the pan. Use your wooden spoon to release all of the brown bits on the pan and stir them in to incorporate into the newly formed liquid.
Once the Dutch oven has been thoroughly deglazed, add the garlic and cook for about a minute stirring constantly so the garlic doesn't burn.