Steak Sauce and Steaks:

Heat the oil in a medium saucepan over a medium high heat grill. Add the shallots, garlic, ginger and Serrano peppers. then cook until tender, about 3 minutes. Add the ketchup, fish sauce, soy sauce, vinegar, sugar, lime juice, chili sauce, cumin, blueberries and 2 tablespoons cilantro. Stir to combine and cook, uncovered, until thickened and slightly reduced, about 10 minutes, stirring occasionally. Pour into a food processor and process until smooth. Transfer to 1 ounce ramekins, or small bowls, for serving and set aside. While sauce is simmering, prepare the steaks. Pat the steaks dry with paper towels. Brush the steaks with oil and sprinkle spice rub evenly on each side of steaks. Gently pat the rub into the meat with fingers. Place the steaks on the grill, directly over medium high heat, for 6 minutes, then close the lid. Turn the steaks, close the lid again, and grill 6 more minutes for medium done. Remove the steaks from the grill to a cutting board, tent loosely with foil, and let rest for 5 minutes before slicing. Garnish each steak with cilantro and serve with a lime wedge and the Blue Chili Steak Sauce on the side.

Thai Spice Rub:

Mix all ingredients in a small bowl until combined. Makes about 1/3 cup.