In small or large pot cook noodles, onions, wnd sweeat peas until egg noodles are done. Mean while drain egg noodles and rince with cold water and set a side. In a large mixing bowl combined mayonnaise, mustard, vinegar, salt snd pepper mix well. When done combined and toss well. Combined shredded cheddar cheese. And toss cheese well. Place lid on boel and place in the refrigerator for 2 hours or until ready to use .