Walnut oil is an excellent choice for health-conscious people. Not only is it a flavorful alternative to olive oil, but it surpasses olive oil in a nutritional comparison. With its intensely nutty aroma and delicious flavor, walnut oil is a natural for salad dressings, or for accenting grilled fish and pasta. Just a drizzle can turn an ordinary dish into something elegant and special.
Place the spinach in a large salad bowl and set aside.
Cook the bacon in a skillet over medium heat until almost crispy. Pour off all but one tablespoon of bacon fat and discard. Add the shallots to the skillet and cook until the shallots have softened and the bacon is browned and crispy, 2 to 3 minutes.
Add the vinegar and mirin to the skillet and raise the heat to high. Cook for 1 minute, then add the walnut oil. Bring the mixture to a rapid boil, stirring constantly to emulsify the dressing. This should take about a minute. Immediately pour the contents of the skillet over the spinach and toss well to combine. Transfer to a platter and garnish with walnuts. Serve immediately.