Use a small melon baller to scoop out the top center portion of the onion (about 1/3 of the way down) to make a well in the center.

Place the onion on a sheet of aluminum foil and add the butter into the well.

Mix the seasonings with the olive oil and pour over the butter into the well, allowing the oil and seasoning mixture to drip down the sides of the onion.

Season with salt and any additional seasonings desired.

Seal the entire onion tightly in the aluminum foil and place it in a small baking dish or cast iron skillet to catch any oil that seeps out.

Remove from the oven and open the foil to check on the onion. The entire onion should be fork-tender and the center should jiggle. If it needs more time, reseal and return it to the oven for another 10 minutes.

Turn the oven to broil. Open the foil, drizzle more melted butter (or olive oil) and an extra pinch of salt. Broil for 5-10 minutes, watching closely to avoid burning.

Peel away the outer layer and enjoy each layer beneath it with an extra sprinkle of salt if desired. Pour all the juices from the foil over the onion when serving.