6 bacon strips, diced
1/4 cup cider vinegar
3 tablespoons brown sugar
9 cups fresh baby spinach
2 unpeeled large red apples, thinly sliced
1 medium red onion, chopped (about 3/4 cup)
In a large skillet, cook bacon until crisp. Remove to paper towels. Drain, reserving 2 tablespoons drippings.
In same skillet, combine vinegar, brown sugar and reserved drippings. Bring to a boil; cook and stir until sugar is dissolved. Cool slightly.
Meanwhile, in a serving bowl, combine spinach, apples, onion and bacon. Drizzle with warm dressing; toss to coat. Serve immediately.