Wash the potatoes and cut any large ones in half. Place them in a pot, cover with salted water, and bring to a boil. Cook for 10 to 15 minutes until tender, then drain and let cool.

Trim the green beans and cook them in boiling water for 3 to 4 minutes until bright and just tender. Drain and rinse with cold water.

Hard boil the eggs by placing them in a pot, covering with water, bringing to a boil, then turning off the heat and letting them sit for 9 minutes. Cool in ice water and then peel.

In a bowl, whisk together the dressing ingredients: olive oil, lemon juice or red wine vinegar, Dijon mustard, salt, pepper, and chopped garlic.

Flake the canned tuna into large pieces.

On a large platter or bowl, arrange the lettuce or mixed greens, add the potatoes, green beans, halved eggs, cherry tomatoes, and olives.

Scatter the tuna and anchovy fillets if using, then drizzle dressing over the salad and toss gently, or serve the dressing on the side.

Finish with a sprinkle of chopped parsley or some turns of black pepper, and serve right away.