In a large skillet over medium heat, cook the bacon until crispy. Drain on paper towels. Allow to cool slightly before chopping. Reserve ½ cup of bacon grease.
In a mixing bowl, combine vinegar and mustard. While whisking, slowly add reserved bacon grease. Season with salt and pepper to taste.
Divide spinach, blue cheese, strawberries, and chopped bacon between 4 plates. Topping with dressing and serve. Enjoy!
Recipe by This Cookin' Dad at http://thiscookindad.com/2015/05/spinach-and-strawberry-salad/