Sweet 'n' Sour Tomato Salad

7 tomatoes, thinly sliced
1 small yellow onion
1/2 cup granulated sugar
1/2 cup distilled white vinegar
1/2 cup vegetable oil
Salt and freshly ground pepper to taste

Thinly slice the tomatoes. Cut the onion in half through root end, then thinly slice into half-circles.

In a large bowl, toss together tomatoes, onion, sugar, vinegar, oil, salt and pepper. If desired, adjust the amounts of vinegar and sugar according to your taste. Serve at room temperature.