Stir together sugar, corn syrup, water, butter, salt and butter flavor. Bring
to simmer over medium heat and place lid on pot for one minute; remove lid. This
will steam all sugar crystals on side of pot into the sugar mixture. Place a candy
thermometer in pan and continue to cook over medium heat, stirring frequently until
candy reaches the soft crack stage.
Add nuts and mix in. Continue to cook until mixture reaches the hard crack stage.
Remove from heat and add baking soda, blending it in completely. Mixture will foam.
Pour onto a nonstick cookie sheet or lightly buttered baking sheet. Spread to 1/4-inch
thick or less while mixture is still hot. Candy will begin to harden quickly.
When set and cool, break into pieces and store in an airtight container.