Grandma Margaret made this every single spring and I finally managed to recreate that perfect sweet balance she was known for.

If you’d like a little extra sweetness and that classic springtime look, lightly sprinkle the top with the remaining 2 tablespoons of brown sugar. Don’t stir it in; just let it sit on top so it can slowly melt into a thin, shiny layer in spots as it chills.
Cover the bowl with plastic wrap and refrigerate for at least 2 hours before serving, or up to overnight. Chilling lets the flavors settle into that perfect sweet balance Grandma Margaret was known for, and the dressing will thicken slightly as it sets.
When ready to serve, uncover and give the salad a very gentle stir just around the edges if any liquid has pooled, but try not to disturb the soft, slightly uneven surface too much. Serve cold, scooping down through the creamy top so everyone gets a mix of grapes and dressing in each spoonful.
Variations & Tips
For picky eaters, you can slice the grapes in half lengthwise so they’re easier for little mouths to manage and feel less like “whole fruit” in a salad. If cutting grapes for very young children, always slice them lengthwise (never just across) to reduce choking risk. For a slightly lighter version, swap half of the sour cream for plain Greek yogurt; this keeps the tang but cuts the richness a bit. If your family prefers things less sweet, reduce the brown sugar in the cream mixture to 1/3 cup and skip the topping sugar, then let everyone drizzle a little honey over their own serving if they want more sweetness. For a dessert-style twist closer to what some grandmas did for Easter, you can sprinkle a small handful (about 1/4 cup) of chopped toasted pecans or walnuts and 2 tablespoons of mini chocolate chips over the top just before serving—kids tend to love the little chocolate surprise. If you need this to sit out on a buffet, keep the bowl nestled in a larger bowl filled with ice to stay cold; because this recipe uses dairy, it shouldn’t be left at room temperature for more than 2 hours (or 1 hour if it’s very warm in the room). Store leftovers covered in the refrigerator and enjoy within 2–3 days for best texture; if any liquid separates, just give it a gentle stir before serving again.