Prep the tomatoes. Core and chop the tomatoes into small chunks.
Place them in a large bowl and sprinkle with a pinch of salt and pepper. If they’re very juicy, let them sit for 5 minutes, then drain off excess liquid so the salad doesn’t get soggy.
Make the dressing. In a small bowl, whisk together the mayonnaise, sour cream (or yogurt), Dijon, lemon juice or vinegar, garlic (if using), 1/2 teaspoon salt, and black pepper. Taste and adjust acidity with a little more lemon juice or a tiny pinch of sugar if the tomatoes are very tart.
Add aromatics. Toss the tomatoes with the sliced red onion and fresh herbs.
This adds bite and brightness.
Wait to crush crackers. Right before serving, lightly crush the crackers with your hands. Aim for a mix of small chunks and crumbs. You want texture—not powder.
Combine gently. Add the dressing to the tomato mixture and fold to coat.
Right away, sprinkle in the crushed crackers and gently mix again. Don’t overwork it or the crackers will break down too much.
Serve immediately. Taste and adjust salt or pepper. If you like a little heat, add a pinch of red pepper flakes on top.
Eat it right away while the crackers are still crisp at the edges.