Sweet and Tangy Pasta Salad

I LOVE pasta salad. This is one of my all time favorite recipes.

16 oz. Penne pasta: cooked, drained, and chilled
1 med. red onion: diced
1 cucumber: diced
1 tomato: diced
2 Tbsp. fresh parsley
1 green pepper: diced
1/2 cup sugar
1/2 cup vinegar
1/2 tsp. ground mustard
1 tsp. garlic salt
2 Tbsp. oil

Heat vinegar and sugar over medium heat until sugar dissolves. Add remaining dry ingredients, whisk together. Allow to cool. Toss over chilled pasta and chopped vegetables. Chill until ready to serve.