If not already done, rinse lettuce thoroughly in cold water, spin or pat dry, and tear into bite-sized pieces. Place the dried lettuce in a large mixing bowl.

Prepare tomatoes and onion

Trim cherry tomatoes and cut each in half. Thinly slice the red onion into half-moons; if raw onion is strong, soak slices in cold water for 5 minutes, then drain and pat dry. Add tomatoes and onion to the bowl with lettuce.

Season salad

Just before serving, add croutons or cucumber if using, then sprinkle the salad with 1/4 tsp salt and 1/4 tsp black pepper. Toss lightly to combine after dressing is added.

Red Wine Vinaigrette

Combine base

In a small bowl or jar, add 2 tbs red wine vinegar, 1 tsp Dijon mustard, 1 tsp honey (or maple), 1 tsp minced garlic, and 1 tbsp finely minced shallot.

Emulsify

While whisking constantly (or with the jar lid on, shake vigorously), slowly drizzle in 6 tbs extra-virgin olive oil until the dressing emulsifies and thickens slightly. If too thick, whisk in up to 1 tbsp cold water to loosen. Season with 1/2 tsp salt and 1/4 tsp freshly ground black pepper, then taste and adjust acidity or sweetness as needed (add up to 1 more tsp vinegar or 1/2 tsp honey).

Rest

Let the vinaigrette sit for 5 minutes at room temperature to allow flavors to meld. If prepared ahead, refrigerate up to 3 days and bring to room temperature and re-whisk before using.

Dress the salad

Just before serving, drizzle about 3 to 4 tablespoons of the vinaigrette over the salad (start with less; you can always add more). Toss gently but thoroughly to coat all leaves and vegetables. Taste and add additional dressing, salt, or pepper if required.