1/4 cup butter
1/2 cup firmly packed golden-brown sugar
2/3 cup light corn syrup
1 tablespoon orange extract
1/4 teaspoon salt
3 cups lightly roasted and skinned hazelnuts
Preheat oven to 350 F.
Spread a large sheet of parchment or waxed paper onto a heatproof surface large enough to hold nuts after they have roasted.
In a heavy-bottomed, medium-sized pot over medium-high heat, melt the butter with the brown sugar and corn syrup. Bring mixture just barely to a boil, then remove pot from burner and stir in the orange extract and salt. With a silicone spatula, stir in the hazelnuts, making sure they all get evenly coated with syrup.
Scrape nuts and all of syrup onto a rimmed baking sheet, spreading them out into a single layer. Bake in preheated oven on center rack for about 20 to 30, stirring about every 5 to 7 minutes with a wide spatula or dough scraper, so they remain evenly coated with syrup.
Depending on your oven, roasting time will vary, so just be watchful. As syrup gets thicker, it will bubble and foam around nuts. Just keep stirring and spreading them in a single layer after each stir. When nuts have reached a lovely golden-brown and syrup is thick and clinging to them, remove from oven and scrape/pour them out onto prepared surface to cool.
While nuts are hot, spread them apart as much as you can (some will insist on remaining in clumps), so they don't touch each other as they cool. It's not a tragedy if some stick together; they break apart very easily once cooled.
When the nuts are completely cool, store in an airtight container. Makes 3 cups.