Sesame Spinach Salad

2 packages (10 ounces each) fresh spinach, torn
1 pint cherry tomatoes, halved
2 ripe avocados, peeled and sliced
1 package (5 ounces) frozen cooked salad shrimp, thawed
3/4 pound fresh mushrooms, sliced
3 hard-cooked eggs, chopped
1/2 cup sesame seeds, toasted
1/4 cup shredded Parmesan cheese

Creamy Dressing
2 cups (16 ounces) sour cream
1 cup mayonnaise
1/4 cup finely chopped onion
2 tablespoons sugar
2 tablespoons white vinegar
1 teaspoon salt
1/2 teaspoon garlic powder

In a large bowl, toss the spinach, tomatoes, avocados, shrimp, mushrooms, eggs and sesame seeds. Sprinkle with Parmesan cheese. In a small bowl, combine the dressing ingredients; mix well. Serve with salad. Refrigerate leftovers. Makes 20 servings.