Finely grate the zest from half the orange and then juice the orange. Put 1-1/2 Tbs. of the juice in a small bowl along with the saffron, and let sit for 10 minutes.
In a food processor, combine the saffron mixture, orange zest, garlic, and mustard and pulse until the garlic is puréed, about 15 seconds. Add the egg yolk and process for 10 seconds. With the machine running, slowly pour the olive oil and vegetable oil through the feed tube until the sauce is thick and well combined. (If you like a thicker texture, add a little more vegetable oil.) Season to taste with salt.
Refrigerate the aïoli for at least 2 hours to let the flavors marry. Fold in the olives just before serving.
Make Ahead Tips
The aïoli will keep for 1 week in the refrigerator.
nutrition information (per serving):
per 1 Tbs.;
Photo: Scott Phillips