Mix the spinach and mushrooms in a salad bowl.
Measure out 4 Tablespoons of bacon fat. If there isn't enough add olive oil to total 4 Tablespoons.
Mix together the cider vinegar, water, brown sugar, pepper and mustard. Set aside.
In a small skillet heat the bacon fat/olive oil mixture over medium heat.
Add the shallots and cook for 4 minutes, then add the garlic and cook just until the fragrance of the garlic releases.
Add the vinegar mixture to the skillet and bring to a boil.
Cook until the mixture reduces by half.
Remove from heat and pour the dressing over the spinach/mushroom mixture. (I like to start with about 1/3 of the dressing and add more as needed.
Serve the salad with the Bacon Twists and the Gorgonzola Croutons.