Add Parmesan, olive oil, vinegar, oregano, Greek yogurt, shallot & mustard to food processor / blender. Puree until smooth. Season to taste with salt & pepper. Cover & refrigerate in an airtight container until use (~3 days).
Set ears of corn over a gas burner on high heat (or on a baking sheet in the oven set to broil on high). Roast until corn is charred all over, turning occasionally (~4 min total). Remove to a cutting board & cut the kernels off the cob.
Heat oven to broil, high. Lay slices of prosciutto on baking sheet in a single layer. Broil until prosciutto is golden (~1-2 min).
Flip the prosciutto with tongs & continue to broil until crispy (~1 min). Be sure to check on prosciutto frequently so it doesn't burn.
Remove to a plate & crumble prosciutto. Set aside until ready to use.
Add butter lettuce & frisée to a large salad bowl. Add ⅓ cup of dressing & toss to combine. Then, add more dressing if desired. Top with corn, crumbled prosciutto, Parmesan & radish slices. Toss to combine once more & serve immediately,