Cut the broccoli into 1-inch florets, halve the grapes lengthwise, and finely dice the red onion. Toast the pecans in a dry skillet over medium heat for 3-4 minutes, stirring occasionally, until fragrant and lightly browned. This brings out their natural oils and deepens their flavor. Set the pecans aside to cool slightly before chopping them into bite-sized pieces.

In a large mixing bowl, whisk together the mayonnaise, balsamic vinegar, sugar, and salt until smooth and fully combined. I like to add the salt to the vinegar first and let it dissolve slightly before mixing with the mayo—this helps distribute the salt evenly and prevents any grainy texture in the dressing.

Add the prepared broccoli florets, halved grapes, and diced red onion to the dressing. Using a spatula or wooden spoon, gently fold the vegetables into the dressing, making sure all the pieces are evenly coated. Work deliberately to avoid breaking the grapes or broccoli florets.

Fold in the toasted pecans from Step 1 just before serving. I add the pecans at the last moment rather than earlier because they can absorb moisture from the dressing and lose their crispy texture. Transfer the salad to a serving bowl and refrigerate for at least 30 minutes before serving to allow the flavors to meld together.