Start by making the popcorn. Add two tablespoons oil and a couple of popcorn kernels to a large pot. Cover and heat the oil over medium-high heat. The oil is ready when the kernels pop. Add the rest of the kernels and cover again. Shake the pan to spread them into a single layer.

Let the popcorn pop for several minutes, shaking frequently. If steam starts to build up, lift the lid a bit to release it. As soon as the popping slows down, remove from heat and wait for all the popping to finish. Transfer the popcorn to a large bowl.

Line a baking sheet with wax paper. Now it’s time to make the caramel! Heat sugar in a small pot or frying pan over medium heat, stirring constantly. The sugar will clump and melt after a few minutes. Be careful not to burn it! Remove from heat as soon as sugar has melted and stir in margarine. If the caramel starts to separate, return to heat and stir until combined. This may take three to five minutes.

Immediately pour over popcorn, stirring as you pour to cover as much of it as you can. Be careful, as the caramel is very hot. Transfer to the lined baking sheet and spread out. Allow to cool completely (about five minutes). Break into pieces.

Sprinkle with salt if desired. Serve immediately or store in an air-tight container at room temperature for up to five days.