• Step 1: In a skillet, cook the diced bacon over medium heat until crispy, about 5-7 minutes. Transfer the cooked bacon to a paper towel-lined plate, reserving the bacon fat in the skillet.
• Step 2: In the same skillet with the reserved bacon fat, whisk together the red wine vinegar, granulated sugar, and Dijon mustard. Cook over medium heat, stirring constantly, until the sugar has dissolved, about 2-3 minutes.
• Step 3: Slowly drizzle in the olive oil while whisking continuously to emulsify the dressing. Season with salt and freshly ground black pepper to taste.
• Step 4: Add the cooked bacon back to the skillet and toss to coat with the hot dressing.
• Step 5: Serve the hot bacon dressing immediately over fresh spinach leaves, tossing to coat the greens.