Toast the nuts until they are fragrant. Set aside to cool.
Bring the sugar, 1/2 cup water and lemon juice to a rolling boil in a saucepan. Cook without stirring but swirling occasionally, until the caramel turns a deep, smoky brown, 7 to 10 minutes. When the caramel is nice and dark, take it off the heat and slowly whisk in the cream. Be careful! The cream will bubble and steam. Return the caramel to the heat, let it come to a boil then remove it immediately. Whisk the butter, honey and salt into the caramel until it is smooth and all of the ingredients are incorporated.