Have all the ingredients at room temperature. In a small bowl, beat the egg yolks with the mustard, 1 tablespoon lemon juice and garlic to taste. Beat in 1/4 cup vegetable oil, drop by drop. This will establish the emulsion. The remaining vegetable oil and the extra virgin olive oil can then be added in a slow steady stream while you continue to beat constantly. Adjust seasoning with lemon juice, garlic, salt and pepper. If the mayonnaise seems too thick, add a drop or two of water. Cover and refrigerate until ready to serve. Yield: 1 cup