This recipe came from my Aunt Agnes, and is the best 3-bean salad that I've tasted. Be sure to use safflower oil--it makes a big difference in the taste!
1 - 16 oz can cut green beans
1 - 16 oz can cut wax beans
1 - 16 oz can kidney beans
3/4 cup onion, chopped
1 cup peppers, chopped (use both red and green peppers for a pretty salad)
1/2 cup safflower oil
3/4 cup vinegar
1 tsp mustard seed
3/4 cup sugar
Drain the green beans, wax beans, and kidney beans. Combine the drained beans with the chopped onion and peppers.
Mix together the safflower oil, vinegar, mustard seed and sugar. Heat this mixture to boiling, and then cool. Pour the mixture over the beans, onion and peppers. Stir, then refrigerate overnight, stirring a couple of time to ensure the ingredients are well mixed.
Stir before serving. This salad keeps well for several days in the refrigerator.