MAKE THE DRESSING
To a blender, food processor, or large cup using an immersion blender, add the mayonnaise, sour cream or buttermilk, lemon juice, Worcestershire sauce, minced garlic, dijon mustard, anchovy paste, and Calabrian chilis.
Blend until smooth and creamy.
Transfer to a bowl, then add the black pepper, parmesan, and chili flakes, stirring until combined.
Taste and adjust anything to your liking, adding more chili flakes or Calabrian chili if you want it spicier. Cover and refrigerate until ready to use.
TOAST THE BREADCRUMBS
In a large skillet over medium heat, add the butter and olive oil and let melt together.
Add the panko breadcrumbs and a pinch of salt, stirring frequently to coat evenly.
Toast for 5 to 7 minutes, stirring often, until deep golden brown.
Remove from the heat and trasnfer to a paper towel lined plate to absorb any excess oil.
Then stir in the parmesan, dried oregano, and a pinch of salt. Set aside to cool slightly.
ASSEMBLE THE SALAD
Wash the little gem lettuce and dry it very well, since any leftover water will keep the dressing from clinging to the leaves.
Separate the leaves and add them to a large mixing bowl. Drizzle the dressing, using as little or as much as you'd like, and toss it to make sure each leaf is evenly coated.
Then transfer to a large serving platter and arrange the leaves.
Sprinkle the toasted breadcrumbs evenly on top.
Finish with a sprinkle of freshly grated parmesan and the chopped parsley before serving.