You will need ten cups of the curd for our Tropical Wedding Cake; make no more than one and a half batches at a time.
Combine sugar, passion-fruit puree, and egg yolks in a medium saucepan, and place over medium heat. Cook, whisking constantly, until thick enough to coat back of spoon, 12 to 15 minutes. Remove from heat; stir in butter, piece by piece, until melted. Cool, cover with plastic wrap; refrigerate until needed, up to three days.