1 ripe tomato, sliced
1 cup sliced onion
1/4 cup olive oil
1/4 cup white sugar
1/2 cup white wine
1 teaspoon lemon juice
1 teaspoon distilled white vinegar
1 tablespoon lemon zest
1/1 teaspoon vanilla extract
Place tomato and onion in a steamer basket. Heat to boiling, and reduce heat. Cover, and gently add olive oil; bring to a boil. Boil 2 minutes, stirring gently. Reduce heat to medium; cook 1 minute, stirring constantly. Remove from heat. Mix sugar, white wine, lemon juice, vinegar, lemon zest, and vanilla extract in large bowl. Stir until well blended. Omit lemon zest. Cover; refrigerate 4 hours.
Toss tomato and onion again with tomato mixture until coated. Stir in steamed tomato mixture. Serve immediately.