For the Pepperoncini Mayo

1. Make a pepperoncini mayo by combining the mayo and 3 tablespoons or
   more of chopped pepperoncini in a small bowl. Set aside.

For the Greek Burgers:

1. Divide the ground beef into four equal parts.
2. Take one of the portions and mix it with ¼ teaspoon salt, ¼ teaspoon oregano, 1/8 teaspoon black
   pepper, and 1 teaspoon chopped pepperoncini. Flatten the mixture and add
   ¼ of the feta to the center. Fold the meat over the cheese then flatten the
   burger into a classic burger patty shape. Apply pressure to the middle with
   your thumb so that the patty will cook evenly. Repeat with the remaining
   meat to create 4 stuffed burger patties.
3. Heat a nonstick pan over medium and add two tablespoons of olive. Cook
   the burgers for a total of 9 minutes, flipping halfway. Depending on the size
   of your pan, you might need to cook these in batches so as not to
   overcrowd.
4. Once you’ve flipped your burger, immediately add 1.5 ounces of
   the sliced Kasseri cheese and let it melt.
5. When the burgers are almost done, toast your buns.
6. Assemble the burgers. Place a tablespoon or more of the pepperoncini mayo
   on the top buns and line the bottom buns with the romaine lettuce. Place
   the burgers on the bottom buns, cheese side up, then add a slice of tomato
   and sliced cucumbers over top. Stick a few kalamata halves on the top buns
   and place the top buns on the burger to close.