Line 3 baking sheets with parchment paper (important to have these ready because you'll have to work fast when they're done).
In a large saucepan, simmer cream, sugar, corn syrup and orange zest slowly over low heat, until reduced (watch carefully for boil over).
Stir continuously as soon as the mixture starts to stick to the bottom of the pan(the mixture will become thicker and turn light brown as is reduces and the sugar carmelizes).
Stir in pecans when the mixture reaches the soft-ball stage (240 degrees), and continue to stir until the mixture starts to pull away from the sides of the pan.
Test by dropping a quarter size amount onto the lined baking sheet, and if it holds a nice rounded top (instead of running out flat), and if it is dull looking (rather than oily/shiny)it is ready (approximately 248 degrees).
Use two dessert spoons to spoon out the pralines onto the baking sheets (one to dip, and one to scrape off) - they're hot, be careful!
Depending on the humidity, temperature, and luck - they may be ready in about 30 minutes, but don't worry - it could take up to a day or two.