The most important thing when making a seared tuna nicoise is to make sure that the tuna is the freshest sushi grade tuna possible. At the supermarket, it must say "sushi grade" tuna. If you want to cook your tuna well-done, then you can use regular tuna steaks. But for me, a perfect tuna nicoise is tuna that is just lightly seared. This photo is a good indication of how fresh the tuna should be. The filet on the left is perfect. The more red the tuna is, usually the most fresh. You want to always look for a filet that is a deep reddish color and without a lot of the white marbling running through it. The filet on the right is still considered sushi grade, but you can tell the color isn't as saturated and it has some of the white marbling which makes it harder to chew, and tastes less fresh.
TUNA NICOISE SALAD
1 6-to-8 ounce filet of fresh sushi grade tuna
Butter lettuce (8 to 10 large leafs)
1/3 pound of haricots verts or French green beans, stems trimmed
1 avocado, peeled and cut into slices
1 pint of grape tomatoes, halved (I used heirloom in these photos)
1/3 cup of nicoise olives, whole and pitted
2 large servings
2 garlic cloves, minced
1 teaspoon Dijon mustard
3 tablespoons red wine vinegar
1/2 lemon, juiced
2 tablespoons chopped fresh flat-leaf parsley
2 tablespoons minced fresh tarragon
Sea salt and freshly ground black pepper
1/2 cup extra-virgin olive oil
To make the vinaigrette: combine all ingredients in a medium sized bowl and whisk vigorously to emulsify. Set the dressing aside while preparing the salad so the flavors can marry.
Start by boiling your eggs and steaming the green beans. Add the eggs to a medium sized pot filled with water so it just covers the eggs. Cook on high heat until boil. The second the water bowls, turn the heat to off and let the eggs cook in the pot for 4 minutes. This will give you a medium-soft boiled egg (which is the way I prefer). They will look like they do in the photos - a creamy dark yellow yolk. After 4 minutes, remove the eggs from the pot and let them cool in a bowl of ice water. (This stops them from continuing to cook). Set aside and let cool.
In the meantime, steam your green beans until crisp-tender, about 5 minutes over medium heat in a steamer basket over simmering water. Remove from heat and strain the beans. I like to put them in a bowl and stick in the fridge (or freezer) to cool down while preparing the rest of the salad.
For the tuna, rub both sides generously with good quality olive oil and season well with salt and pepper. Drizzle some of the vinaigrette over both sides. Lay the tuna filet on a hot skillet over medium-high heat and sear for 30 seconds on each side for a light sear. If you want a medium sear, then cook for a minute each side. For fully cooked through, cook for about 2 1/2 minutes on each side. Remove the tuna from the hot pan and transfer to a cutting board. Let cook while you assemble the salad.
Grab two large salad plates or bowls. Assemble the butter lettuce leafs down first so they cover the bottom of the plate. Next, add your green beans to the middle of the plate. Around the outside of the green beans, add the sliced avocado, halved tomatoes and olives. Keep ingredients separated. Grab your cooled eggs and carefully peel the shells away. Slice in half and place two halves together (again, outside of the green beans so the beans are surrounded by all the other "goodies").
Lastly, the tuna! Using a sharp knife, slice the tuna lengthwise (I like to slice fairly thin). Discard any pieces that have that white marbling as it's hard to chew. Arrange the tuna right on top of the green beans (splitting it up between the two dishes). Drizzle your salad with the herb vinaigrette and enjoy!