Step 1

Place anchovies in a shallow dish or small serving bowl and drizzle vinegar over. Let sit 5 minutes, then add peperoncini. Finely grate zest from half of lemon over anchovies. Slice lemon in half and squeeze in juice from both halves; drizzle with oil.

Step 2

Scoop butter into a small dish and sprinkle generously with salt and pepper if desired. Serve marinated anchovies with bread and butter alongside.