Place the cumin seeds in a small frying pan and sauté over medium heat for two minutes, or until they brown. Remove from heat. Finely grind half of the cumin seeds in a coffee grinder or with a mortar and pestle. In a blender or food processor, combine the egg, mustard, salt, garlic and the ground cumin seeds. Process quickly to blend. With the processor running, add the olive oil until the aioli is emulsified. If the mixture seems too thick, add a spoonful or two of water. Scrape the mixture into a bowl and stir in the whole cumin seeds. Cover and refrigerate. Serve with beef or pork dishes or on sandwiches.