This rouille is like aioli, only fired up with cayenne pepper and laced with fragrant saffron. Try with: shellfish, grilled fish, or pork, bouillabaisse.
Crush saffron, and place in a medium bowl. Pour 1/4 cup boiling water over; steep 15 minutes.
Meanwhile, chop garlic, and add a pinch of salt. Mash into a paste with a knife's flat side or a mortar and pestle.
Add bread to saffron water; press to absorb.
Add egg yolk; stir to combine. Gradually add 1/4 cup oil, drop by drop, stirring constantly, until smooth. Stir in remaining oil in a steady trickle.
Stir in garlic, cayenne or chiles, and paprika, and season with salt.
To store, refrigerate, covered, up to 2 days.