Danish Lettuce Salad

Ingredients

• 1/2 lb. crisp bacon, crumbled (set aside)
• 1 head lettuce, broken into bite size pieces
• 1 1/2 sticks finely chopped celery
• 1 small red onion, sliced very thin
• 1 c. sour cream
• 1/4 c. sugar
• 1/2 c. mayonnaise
• 2 tsp. vinegar
• 1/2 c. grated Parmesan cheese