In a small bowl, stir together the flour, bread crumbs, salt, black pepper and garlic powder. Set aside.
To deep fry the jalapenos, heat oil in a large heavy bottom saucepan or cast-iron skillet. Once oil reaches 365 degrees F, working in batches use a slotted spoon to slowly lower the flour coated jalapenos into the hot oil. Cook jalapenos until crispy and golden brown, then use a slotted spoon to transfer fried jalapenos to a paper towel line plate. Repeat frying process with remaining jalapenos. (To oven bake/fry the jalapenos, see notes.)
For Ranch Mayo: In a small bowl stir together ranch seasoning, mayonnaise and buttermilk, until thoroughly mixed.
To oven bake/fry the jalapenos: Preheat oven to 420 degrees F. Line a baking sheet with foil and spray foil with cooking spray. Place flour coated jalapenos in a single layer on the baking sheet. Spray the top of the jalapenos with a thin layer of cooking spray. Bake in preheated 420 degree F oven for 10-12 minutes, or until crispy and golden brown. Remove sheet pan from oven and flip the jalapenos over. Return the jalapenos to the oven and cook for an additional 3-4 minutes or until golden brown on the other side. Serve immediately.
*Pickled jalapenos can be substituted for the fresh jalapenos, but will need to be drained and patted dry with a paper towel before using.