In a large stainless steel saucepan, melt butter over medium heat. Add brown sugar, condensed milk, and corn syrup; bring to a boil. Cook, stirring constantly, until a candy thermometer registers 236°. Stir in vanilla. Remove from heat; let stand until cooled to 200°. (Do not stir.)
Line a baking sheet with foil. Dip each pear halfway into caramel, letting excess drip off. Sprinkle with salt. Place on prepared pan. Let stand until caramel is set. Dip in melted chocolate and sprinkle with hazelnuts, if desired.
Recipe by Southern Lady Magazine at https://southernladymagazine.com/chocolate-salted-caramel-pears-recipe/