Combine the sugar, cream, and orange rind in a heavy 2-quart saucepan.
Cook over medium heat, stirring constantly, to 234°, or until a little of the syrup forms a soft ball when dropped in cold water.
Remove from the heat; add the butter and, without stirring, cool to lukewarm (110°).
Beat until the mixture loses its gloss.
Beat in the pecans and currants.
Spread in an 8-inch square buttered pan.
Cool until firm, then cut into squares.