Source: Southern Living

1/2 cup sour cream
1/2 cup mayonnaise
1 green onion, chopped
2 tablespoons prepared horseradish
1/2 teaspoon salt
1/2 teaspoon pepper
8 (12-inch) flour tortillas
1 pound cooked roast beef, cut into 24 thin slices
2 (6 ounce) packages sharp Cheddar cheese
2 cups shredded lettuce

Stir together first 6 ingredients until blended. Spread evenly on one side of each tortilla; top with 3 beef slices and 2 cheese slices. Sprinkle evenly with shredded lettuce. Roll up tortillas tightly; wrap in plastic wrap and chill 8 hours.

If using for snacks, cut into 1-inch slices.