Preheat oven to 350° and put a 10-in. cast-iron skillet* into oven to heat.
Drain marinade from 1 jar of artichokes into a frying pan. Drain remaining artichokes; reserve marinade for other uses. Chop all artichokes.
Heat marinade in frying pan over medium heat. Add onion and garlic and cook, stirring, until onion is soft, about 5 minutes.
Whisk eggs in a bowl to blend. Stir in bread crumbs, pepper, oregano, and hot sauce. Stir in cheese, parsley, artichokes, and onion mixture.
Remove skillet from oven. Protecting your hands, wipe it quickly with an oiled paper towel. Pour in custard and bake, uncovered, until custard feels set when lightly touched, about 30 minutes. Let sit at least 15 minutes before cutting into 1-in. squares.
*Use artichokes in an oily marinade; we like Cara Mia brand. Using a skillet (our update on the original baking pan) gives the nibbles a golden crust.
Make ahead: Up to 1 day, chilled. Reheat, uncovered, 12 minutes at 325°.