Preheat oven to 425 degrees F. Place shishito peppers on a baking sheet and toss in oven for 4-6 minutes to get a little roasted. Remove from oven and let cool for a minute or two. Once cool, chop and set aside.
In a large mixing bowl add cream cheese, mayo, shredded cheese, salt and pepper and mix with a hand mixer until fully combined. Add chopped shishito peppers and mix with a rubber spatula until evenly distributed.
Use a rubber spatula and pour mixture into a cast iron dish, preferably a smaller one, not a large cast iron skillet.
Prepare topping by mixing crushed pretzels and melted butter together. Then, pour on top of dip and smooth over with a rubber spatula so it's an even layer.
Toss pretzel covered dip into the oven and bake for 12-15 minutes until warm and gooey.
Serve immediately with chips!
