Image credit to: Boston Organics
Heat the oil and one kernel of popcorn in a large pot over medium heat. Cover with lid or splatter screen. When the test kernel pops, your oil is ready.
Add the remaining popcorn kernels and 1 tablespoon of rosemary, and then shake the pot to gently toss the kernels until they are all coated with oil. Cover with a splatter screen or a lid that is placed slightly ajar to allow the steam to escape.
Cook until the popcorn popping frequency slows to several seconds between pops. Remove from heat, allow a minute or two for any final pops, and then pour into a large bowl.
In a small saucepan combine the butter and remaining 1/2 teaspoon of rosemary. Melt the butter over medium heat.
Drizzle over the popcorn and season with salt and pepper, tossing occasionally as you butter, salt, and pepper the popcorn.