Pear Walnut Salad

2 large heads of Romaine lettuce
1 lb. bacon, cut in 1/2" pieces and cooked
3 pears, cut into chunks with or without skin
12 oz. crumbled gorgonzola cheese
1 1/2 cups broken walnuts
Dressing

Dressing:
1 1/2 cups apple cider vinegar OR balsamic vinegar
1 cup sugar
3/4 cup oil
1 medium red onion
1/2 teaspoon salt
1/2 teaspoon pepper
1 1/2 teaspoon dry mustard
2 tablespoons poppy seeds

Cut the red onion into 1" cubes. Put all ingredients in a blender and mix. Toss salad, add dressing, and serve.