Line a baking sheet with Gefen Parchment Paper and grease with cooking spray. Set aside one and a half cups of potato chips. Break the remaining chips in half if they are large.

In a large saucepan, heat margarine, sugar, vanilla, and vinegar over medium-high heat and cook, stirring occasionally, until the mixture is light amber, and a candy thermometer registers 320 degrees Fahrenheit, about 10 minutes. (It’s important to make sure it reaches the correct temperature.) Remove from heat and stir in four and a half cups potato chips, then immediately pour onto the baking sheet and spread in a thin layer. Gently press the reserved chips on top of the toffee and let cool.

Melt chocolate in a small pot over very low heat, stirring as it melts to prevent burning, until smooth and silky. Alternatively, put about three-fourths of the chopped chocolate in a microwave-safe glass bowl and microwave for 30 seconds. Stir, then continue to microwave in 30-second intervals, stirring between each, until melted. Add the remaining chocolate and stir until smooth, about three minutes. Drizzle chocolate over toffee and set aside until hardened, about 20 minutes. Break toffee into pieces to serve.