Whisk together the olive oil, thyme, salt and pepper in a small bowl. Place the baguette cubes in a large bowl and drizzle with the thyme mixture; toss to combine. Place the bread in a single layer on a nonstick baking sheet and bake until crispy, 10 to 12 minutes, turning once.
Whisk together mayonnaise, buttermilk, dill, onions, white wine vinegar and garlic to make the dressing. Combine the tomatoes, carrots, cucumbers and lettuce in a large bowl and mix together. Pour over the dressing and toss together. Plate the salad and top with the ham, cheese and hard-boiled eggs.