Cut off and discard the stem of each jalapeño. Cut each pepper in half lengthwise, and then into four chunks, with the seeds. Place into the bowl of a food processor fitted with a metal “S” blade. Add the garlic, scallions, oil, ketchup, paprika, and sugar. Pulse until a smooth sauce forms.

Cut the filet split in half lengthwise. Then, slice crosswise into half-inch-thick strips to make bite-size pieces. Place the strips into a large bowl. Add the sauce and toss to coat.

Spray a large frying pan or skillet with nonstick cooking spray. Heat over medium-high until hot but not smoking. Add the beef in a single layer. Do this in batches if necessary. Cook for three minutes until the meat begins to caramelize and brown. Using tongs, turn each piece and cook for three minutes on the second side.

Serve over rice or couscous. Garnish with sliced scallions.