Line bottom of an 11 x 17-inch jelly-roll pan with parchment paper or wax paper; coat paper with cooking spray.
Place cashews and 6 tablespoons sugar in a food processor; process 30 seconds or until cashews are very finely chopped (do not form a nut butter).
Combine remaining 3/4 cup sugar, 1 1/3 cups water, and saffron in a 3-quart saucepan. Bring to a boil over medium heat, and cook, stirring constantly, until a candy thermometer registers 230° and syrup falls in double-threads from spoon, about 8 to 10 minutes. Gradually stir in cashew mixture. Add butter and cardamom; cook 2 to 3 minutes or until mixture thickens and resembles loose dough, stirring consta/'.ntly.
Turn out into prepared pan; quickly spread with a lightly greased offset spatula to 1/4-inch thickness, forming a 9 x 7 1/2-inch rectangle. Cool completely. Cut fudge into 56 (1-inch) diamond-shaped pieces.
Cashews Indian cooks use nuts like cashews for flavor, richness, and sometimes for their sauce-thickening quality. Ground cashews can be used anywhere you would use ground peanuts (as in the recipe for Cashew Fudge). When taken a step further and finely ground into cashew butter, the nuts thicken and flavor classic Indian curries like murgh makhani. Look for raw (unroasted and unsalted) cashews. It's rare to find cashews sold in the shell because the shell contains a toxic substance. But when the shell is removed, the nut inside is perfectly safe and absolutely delicious.