Make the dressing: In a skillet whisk together bacon drippings with browned bits, olive oil, red wine vinegar, dijon and honey. Season with salt and pepper to taste. Allow to simmer over medium heat 1 minute. Stir in 2 slices crumbled bacon. Allow to cool slightly.
Assemble the salad: In a large salad bowl, toss together spinach, remaining bacon, mushrooms, red onion and swiss. Drizzle with warm dressing and toss. Add eggs and croutons to top and serve.