Heat oil in a 3-quart saucepan on medium-high heat.
Put 3 popcorn kernels into the oil and cover the pan.
When the kernels pop, remove them and add the rest of the 1/2 cup of popcorn kernels, making sure they are in an even layer. Let sit off of the heat for 30 seconds. This method makes sure the oil is heated at the right temperature, and then brings all kernels to near-popping temperature so that once added to the heat they all pop at about the same time.
Return pan to heat. Once the popcorn starts popping, gently shake the pan by moving it back and forth over the burning, holding the lid in place.
Keep the lid slightly ajar to let the steam escape; this will keep your popcorn crisper and drier.
Melt butter in microwave.
Add lemon zest and red pepper flakes to melted butter. Pour butter mixture over popcorn.
Add parsley, salt, and pepper to popcorn.
Toss until all kernels are coated and serve immediately.
I generally use 1/4 cup of kernels (which makes 2-3 cups of popcorn) for one serving – because I LOVE popcorn, and have to have plenty to munch on. I suggested this recipe will serve 2-4 people, just depending on what portion size you want to serve.