Stir together first 4 ingredients in a small bowl until well blended.
Spread about 1 tsp. cream cheese mixture evenly onto 1 side of each roast beef slice; top each slice with 1 pretzel stick, and roll up. Serve immediately, or chill up to 1 hour.
Horseradish-Dijon Pretzel Poppers: Omit shredded Cheddar cheese, jalapeño pepper slices, and garlic powder. Stir together cream cheese, 1 Tbsp. finely chopped green onions, 1/2 tsp. prepared horseradish, and 2 tsp. Dijon mustard until blended. Proceed with recipe as directed.