2 ripe avocados
Juice of 1 lemon
1 tablespoon mayonnaise
1 teaspoon grated onion
Salt and freshly-ground pepper, to taste
3/4 cup vegetable oil
1/4 cup white wine vinegar

Mash avocados until smooth with a silver fork or wooden spoon. Add lemon juice, mayonnaise, onion and salt and pepper to taste. Mix thoroughly.

In a separate bowl, blend vegetable oil with white wine vinegar. Stir this into the avocado mixture.

Serve over peeled and sliced tomatoes or toss with a green or seafood salad.