In a small bowl, sprinkle the gelatin over 2 tablespoons of cool water and let sit until absorbed, about 5 minutes. Put the bowl in a pan of hot water and stir to melt the gelatin.
In a blender or food processor, combine the gelatin mixture, the egg and egg yolk, mustard, sugar, garlic, and herbs and process until smooth. With the machine running, add the oil in a slow steady stream (just drips at first, adding more rapidly once the mayonnaise begins to thicken) to make a very thick mayonnaise. Stop and add the lemon juice and vinegar once the mixture begins to thicken and then add the remaining oil, stopping just before it has thickened to your liking. It will thicken a bit more once it is chilled.
Scrape into a small bowl, season with salt and pepper, and cover the surface with plastic wrap. Chill until ready to use. The mayonnaise will keep 3 or 4 days in the refrigerator, though the garlic flavor will intensify over time. Makes 2 cups.
Consumption of raw or undercooked eggs, shellfish and meat may increase the risk of foodborne illness.