1 1/4 lbs bluefin tuna
= (four 5-oz fillets cut abt 1 1/4" thick)
4 servings olive oil cooking spray
1/2 tsp table salt, or to taste
1/4 tsp freshly-ground black pepper, or to taste
1 Tbs butter
2 small shallots - (or 1 large), chopped
1 cup fat-free creamer
4 tsp grainy mustard
1 Tbs chopped fresh dill
1 Tbs lemon zest


Preheat grill to medium. Coat tuna with olive oil cooking spray; sprinkle with 1/4 teaspoon of salt and 1/8 teaspoon of pepper, or to taste. Grill 4 to 6 minutes per side, until desired degree of doneness.
Meanwhile, brown butter in a small saucepan over medium-high heat. Add shallots and cook until they begin to brown, about 1 minute. Reduce heat to medium and add half-and-half; cook until slightly thickened and mixture coats the back of a spoon, about 5 minutes. Stir in mustard; remove from heat and stir in dill, zest, 1/4 teaspoon of salt and 1/8 teaspoon of pepper.
Serve sauce hot or at room temperature.