Heat butter and oil in a 10-inch cast iron skillet over medium heat until butter melts and foaming subsides. Add pepperoni and cook, stirring, until pepperoni begins to crisp, about 2 minutes. Add pepper flakes and garlic and cook, stirring, until fragrant, about 1 minute. Add parsley and chives and stir to combine. Transfer mixture to a large bowl and stir in Parmesan cheese. Do not wipe out skillet.

On a lightly floured surface, divide dough into 2 even pieces. Working one piece at a time, roll or stretch into an oblong about 8 inches long and 4 inches wide. With a bench scraper or knife, cut crosswise into 12 strips. Repeat with other half of dough.

Tie each strip into a knot and transfer to bowl with pepperoni/garlic mixture. Toss and fold with your hands until every knot is thoroughly coated in mixture. Transfer the knots to the skillet in a single layer. Drizzle with more olive oil, cover tightly with plastic, and set aside until doubled in size, about 4 hours. Alternatively, refrigerate until doubled in size, 12 to 16 hours.

When ready to bake, preheat oven to 425°F (220°C) and adjust oven rack to center position. Unwrap garlic knots. Sprinkle with Romano cheese. Transfer to oven and bake until golden brown and crisp, 25 to 30 minutes.

Remove from oven and immediately brush with more extra-virgin olive oil and sprinkle lightly with more Parmesan. Serve right away with warmed sauce on the side.