Preheat oven to 350°F (175°C). Toss brioche cubes with melted butter and olive oil, salt, and pepper in a bowl until evenly coated. Spread in a single layer on a rimmed baking sheet.

Bake croûtons for 8–12 minutes, stirring once halfway, until golden and crisp. Remove from oven and immediately rub the warm croûtons with the cut side of the halved garlic clove to impart a gentle garlic aroma. Let cool on the pan.

Champagne Vinaigrette

In a small bowl or jar combine champagne vinegar, Dijon mustard, honey, minced shallot, and lemon juice. Whisk to blend.

Slowly whisk in the extra-virgin olive oil until the dressing emulsifies and thickens slightly. Season with 1/4 tsp salt and 1/8 tsp freshly ground black pepper and taste; adjust seasoning or acidity as needed. If making ahead, refrigerate up to 3 days and bring to room temperature before using, whisking again to re-emulsify.

Salad

Place the mixed organic greens in a large salad bowl. Add halved cherry tomatoes, sliced cucumber, thinly sliced red onion, julienned carrot, shredded radish (if using), and chopped fresh herbs.

Just before serving, drizzle about 3–4 tablespoons of the champagne vinaigrette over the greens (start with less; you can always add more). Gently toss the salad with salad tongs until the leaves are evenly coated. Season with 1/4 tsp kosher salt and 1/8 tsp freshly ground black pepper, tasting and adjusting if needed.

Top the dressed salad with the warm brioche croûtons, scattering them evenly so they remain slightly crisp.

Optional Add-on

To add grilled chicken: brush the chicken breast with 1 tbsp olive oil and season both sides with 1/4 tsp salt and 1/8 tsp black pepper. Grill over medium-high heat (or pan-sear) 5–7 minutes per side depending on thickness, until internal temperature reaches 165°F (74°C). Let rest 5 minutes, then slice thinly against the grain.

Arrange sliced grilled chicken over the plated salad and serve immediately.