Orange Pretzel Salad

2-1/2 cups crushed bowtie pretzels
3/4 cup margarine
3 Tablespoons brown sugar
8 oz. low fat cream cheese, softened
3/4 Cup Sugar (or Splenda)
8 oz. Cool Whip (can use the low cal. version)
6 oz box Orange Jello (can use sugar free)
1 large can mandarin oranges, drained

Preheat oven to 350
In microwave, melt butter and brown sugar, stirring every 45 seconds until melted. Stir in crushed pretzels. Spread mixture in 9"x13" pyrex pan. Allow to cool.
Cream together cream cheese and sugar then fold in Cool Whip and beat until smooth. Spread over cooled pretzel layer.
Using speed set recipe on Jello box, prepare Jello. Allow to set 5 minutes in refrigerator, then stir in mandarine oranges. Pour over cream cheese layer. Chill until set, then cut into squares.