Aunt Laura's Spinach and Swiss Salad (from the Ivory Favorites Cookbook)

1 large head of iceberg lettuce, torn
1 (10 oz.) bag fresh spinach, torn
1/2 red onion, chopped
3/4 cup sliced mushrooms
3/4 cup grated or small cubes Swiss cheese
1/2 pound bacon, cooked and crumbled
1 cup cottage cheese, drain off liquid in small colander
croutons

Dressing:
1 cup sugar
2 tsp. dry mustard
1 tsp. salt
2/3 cup apple cider vinegar
2 cups vegetable oil
1 Tbsp. poppy seeds

Mix together dressing ingredients in a blender. Store in refrigerator until ready to use. Toss all salad ingredients together and add dressing. This makes more dressing than you need for one salad. It makes a lot! I just add the dressing right before serving to avoid sogginess.