Heat oven to 375 F. Wrap garlic head in aluminum foil and bake for 1 hour. Let garlic cool in foil for 5 minutes, then remove. When cool enough to handle, cut 1/4 inch off bottom and squeeze out pulp. In the bowl of an electric mixer, combine 2 tablespoons of the pulp with egg yolk and lemon juice on high speed. With the mixer running, add a few drops of oil and mix until emulsified. Slowly add remaining oil in a steady stream. Season with salt and pepper. NOTE: Raw eggs should not be used when preparing foods for the very young, the very old, or anyone whose health is at all compromised.