Mandarin Orange Pretzel Salad/Dessert

3 T. sugar
2 c. crushed pretzels (not too fine)
3/4 c. melted butter
8 oz. cream cheese
1/2 c. powdered sugar
1 8 oz. container cool whip
2 c. mini marshmallows
2 (3 oz.) pkg. orange jello
2 c. boiling water
2 small cans mandarin oranges

Mix first three ingredients; press in 9x13" pan; bake at 350* for 15 minutes (will be bubbly); cool.  Whip cheese and sugar separately; fold in cool whip and marshmallows; spread over baked layer.  Dissolve Jello in boiling water; add oranges; chill until slightly thickened; spread over cheese mixture; chill.