3/4 c. cooking oil
1 egg (plus enough water to make 3/4 c.)
1 tbsp. lemon juice
1/2 tsp. dry mustard
2 tsp. salt
2/3 c. sugar

In a quart size saucepan, mix 2/3 cup flour and 1/2 cup vinegar (may add a little water if you think vinegar is too strong). Bring to a boil, then blend into the other ingredients. Beat with an egg beater until very smooth.