Preheat the oven to 375°F (190°C). Toss bread cubes with 1 tablespoon olive oil (or melted butter), garlic powder, 1/4 teaspoon salt and oregano until evenly coated. Spread in a single layer on a baking sheet and bake 8–12 minutes, tossing once, until golden and crisp. Cool on the sheet; set aside.

Make the rainbow slaw

In a large bowl combine shredded red and green cabbage, carrot, red bell pepper, sliced onion (or scallion) and chopped parsley/cilantro. Toss to mix.

If you prefer a slightly softer slaw, sprinkle 1/2 teaspoon salt over the slaw, toss and let sit 8–10 minutes, then drain any excess liquid and pat lightly with paper towel before continuing.

Whisk the dressing

In a small bowl or jar combine 3 tablespoons olive oil, 2 tablespoons apple cider vinegar (or lemon juice), 1 teaspoon honey, 1 teaspoon mayonnaise (if using), 1 teaspoon Dijon mustard, 1/2 teaspoon minced garlic, 1/2 teaspoon salt and 1/4 teaspoon black pepper.

Whisk vigorously or shake the jar until emulsified. Taste and adjust acidity or seasoning — add more honey to sweeten, more vinegar to brighten, or a pinch more salt as needed.

Assemble the salad bowl

Place 6 cups of mixed salad leaves into a large bowl or divide between bowls for individual servings.

Add 2 cups of your chosen sandwich filling (for example: chopped chicken salad, drained tuna salad, sliced deli meats and cheese, or warm roasted vegetables) in a central mound over the leaves.

Top and surround the sandwich filling with 1 to 1 1/2 cups rainbow slaw. Toss gently if you want the slaw mixed into the greens, or leave it piled for contrast.

Drizzle 2–3 tablespoons of the prepared dressing over the salad (start with less; you can add more after tasting).

Scatter 1/2 to 3/4 cup of the cooled croutons over the top and add any optional toppings: 1/4 cup shredded cheese, 1/2 cup tomatoes, 1/4 cup cucumber and 2 tablespoons toasted seeds or nuts as desired.

Gently toss entire bowl if you prefer everything combined, or serve composed with dressing and croutons on top. Serve immediately so croutons remain crunchy.