Step 1: Smooth the Creamy Base - Add the sour cream and mayonnaise to a medium mixing bowl. Stir them together until the mixture looks completely smooth and no streaks of mayonnaise remain. Starting with a smooth base helps the seasonings spread evenly later, so take an extra few seconds to scrape the bottom and sides of the bowl. I like using a flexible spatula or a sturdy spoon because either one makes it easy to press out any small lumps.
Step 2: Add the Onion, Herbs, and Seasonings - Sprinkle in the dried minced onion, dried parsley, dried chives, garlic powder, salt, and black pepper. Try to scatter the seasonings across the surface instead of dropping everything into one pile. This makes the next round of stirring quicker and helps prevent a pocket of salt or garlic powder from hiding in one part of the bowl.
Step 3: Stir Until Fully Combined - Stir the dip until the onion, herbs, and seasonings are distributed evenly. Scrape around the sides and across the bottom of the bowl as you work. The dip should look thick, pale, and creamy, with green herbs and small onion pieces visible throughout. Give it a small taste if you would like, but remember that the flavor will become fuller after chilling.
Step 4: Cover and Chill the Dip - Cover the bowl tightly and place it in the refrigerator for at least one hour. This resting period is where the dip really comes together. The dried onion and herbs slowly absorb moisture from the sour cream, which softens their texture and carries their savory flavor through the entire bowl. You can leave the dip in the refrigerator for several hours or overnight when preparing it ahead.
Step 5: Stir and Check the Texture - Remove the chilled dip from the refrigerator and give it another thorough stir. It will usually feel thicker than it did when you first mixed it because the dried ingredients have absorbed some of the moisture. If it seems firmer than you prefer, stir in a teaspoon of milk at a time until it reaches the texture your family likes. Most of the time, I serve it exactly as it is.
Step 6: Serve Cold With Your Favorite Dippers - Spoon the dip into a clean serving bowl and place it on the table while it is still cold. Surround it with ridged potato chips, crackers, pretzels, or fresh vegetables. Ridged chips are my first choice because they are strong enough to scoop up a generous amount without snapping. Keep an eye on the bowl, because somebody in the family will usually start scraping the sides before you expect it.