Pulse egg, 1 teaspoon olive oil, and salt in a food processor. Combine safflower oil and a scant 1/2 cup extra-virgin olive oil. With machine running, add oil, 1 drop at a time until beginning to thicken, then very slowly pour in remaining oil until emulsified. Blend in lemon juice. Transfer to a bowl. Refrigerate until ready to use (up to 2 days).