Heat up your griddle on medium heat for 10 minutes.
Drizzle the oil onto the center of your griddle.
Add the popcorn kernels.
Let the kernels warm up. Once you start to see the oil sizzle, turn the heat down to medium-low and cover the kernels with the dome.
Keep cooking until you hear the kernels start to pop. Using a grill mitt, grab the dome and slowly keep it moving in circles so that the popped kernels do not burn. Do not lift the dome while doing this.
Keep moving and cooking until the kernels go for 1-2 seconds without anything popping.
Slide the dome to a cooler area of the grill if possible. Remove the lid. Using a spatula, transfer the cooked popcorn to a medium bowl.