Beat cream cheese in a bowl with an electric mixer at medium speed for 30 seconds. Beat in sour cream and peperoncini brine until mixture is smooth. Beat in peperoncini, giardiniera, red onion, Italian seasoning, salt, and crushed red pepper until combined.
Chill, covered, to allow flavors to meld, at least 1 hour (or up to 1 week). Serve with baguette slices, potato chips, and/or vegetables for dipping.
