Line your pan with parchment, leaving an overhang to lift the bars later.

Make the nougat: beat 1/2 cup peanut butter with 1/2 cup butter until smooth. Add 1 tsp vanilla then gradually mix in 1–1 1/2 cups powdered sugar until you have a spreadable, soft dough. Press evenly into the lined pan and chill until firm (20–30 minutes).

Make the caramel: for a quick method, simmer the 14 oz sweetened condensed milk with 2 tbsp butter until it thickens and turns golden, stirring constantly. For a classic caramel, cook 1 cup sugar until amber, whisk in 1/2 cup cream and 1/2 cup butter (use caution — sugar is extremely hot). Stir in 1/4–1/2 cup peanut butter if you like a peanut-caramel flavor.

While the caramel is still warm and pourable, spread it evenly over the chilled nougat. Sprinkle chopped roasted peanuts across the top and press gently so they stick. Chill again until the caramel is firm (about 30–60 minutes).

Remove the slab using the parchment overhang. Cut into bars with a sharp knife (warm the knife under hot water and dry between cuts to get clean edges).

Melt chocolate in a double boiler or microwave in 20–30 second bursts, stirring between intervals. Add a tablespoon of oil if you need the chocolate smoother for dipping.

Dip each bar into the chocolate or pour chocolate over each bar on a wire rack. Place on parchment. Sprinkle with flaked sea salt if desired.

Chill briefly until the chocolate sets, then enjoy.