Rinse and spin-dry the spring mix; place in a large salad bowl. Peel the carrot and cut into matchsticks or shred to yield about 1 cup. Thinly slice the red cabbage to make 1 cup. Halve the cherry tomatoes and dice or shred the cheddar into small pieces. Add carrots, cabbage, tomatoes, and cheddar to the bowl with the greens.

Season the assembled salad lightly with 1/2 teaspoon kosher salt and 1/4 teaspoon freshly ground black pepper. Toss gently to combine so the vegetables and cheese are evenly distributed.

If using toasted sunflower seeds or sliced almonds, sprinkle them over the salad just before serving for crunch.

Champagne Vinaigrette

Make the vinaigrette

In a small bowl or a jar with a tight lid, combine 3 tablespoons champagne vinegar, 1 teaspoon Dijon mustard, 1 teaspoon honey, 1 tablespoon finely minced shallot, and 1 teaspoon freshly squeezed lemon juice. Add 1/4 teaspoon salt and 1/8 teaspoon black pepper. Whisk (or close the jar and shake) to blend the ingredients.

Slowly drizzle in 6 tablespoons extra-virgin olive oil while whisking continuously to emulsify the dressing. Taste and adjust seasoning — add a pinch more salt, a squeeze more lemon, or a little more honey if you prefer sweeter balance. The finished vinaigrette should be bright, slightly tangy, and smooth.

Dress the salad

Just before serving, pour about 3 to 4 tablespoons of vinaigrette over the salad (start with less; you can add more to taste). Toss gently but thoroughly to coat the greens and vegetables evenly. Taste and add more vinaigrette, salt, or pepper as desired.