To prepare the pistachio relish, combine egg yolks, garlic, mustard, salt and pepper in a small bowl using a wire whisk. Gradually add the oil, whisking vigorously in order to fully emulsify the ingredients. Add the pistachios and lemon juice and stir just until evenly combined. Set aside in a refrigerator.

For the tomato stew, heat a casserole or saucepan over medium-high heat until hot. Add the olive oil and as soon as it ripples, add the onion, garlic and saffron and cook, stirring occasionally for 3 to 4 minutes, or until the onion is translucent and just beginning to color.

Stir in the tomatoes, cook for a few seconds and then cover and decrease the heat to low.

Cook for 20 minutes to blend the flavors.

Just before serving, warm 2 tablespoons olive oil in a medium non-stick pan over medium heat. Sprinkle the filets with salt and pepper before adding them to the sauté pan. Sear the filets for approximately 2 minutes on each side or until cooked through and lightly browned.

On a serving platter, lay a bed of the tomato stew, place the fish on top of the tomatoes and scoop the relish along on center of the filets. Serve immediately.