Put oil and popcorn kernels in a large pot over medium-high. When the first kernel pops, cover the pot and remove it from the heat for about 30 seconds.
Place pot back on the stove and once kernels start popping, vigorously shake the pot back and forth, keeping it on heat. Once popping slows, take pot off the heat and remove cover. Put popped popcorn in a large bowl.
Pour melted butter over popcorn and add brown sugar and salt. Toss until popcorn is coated in butter, sugar, and salt.
Feel free to use more or less brown sugar and salt depending on your preferences.