In a mixing bowl, combine sour cream and mayonnaise until smooth. Use a rubber spatula or whisk and mix for about 30–45 seconds until fully incorporated and silky.
Gradually fold in the shredded sharp cheddar cheese in two additions to distribute evenly and avoid clumps.
Mix until well combined. Scrape the sides and fold gently so the mixture stays light and cheesy—avoid overbeating. Taste and add a pinch of salt or a little black pepper if desired.
Cover and refrigerate for at least 1 hour before serving to allow flavors to meld. For best flavor, chill 2–4 hours.
Serve with crackers, veggies, or chips. Garnish with chives and crumbled bacon if using.
Notes
Store dip in an airtight container for up to 4 days. For best texture, avoid freezing.