Combine the maple syrup, vinegar, and red pepper flakes in a small saucepan. Turn the heat to high and boil for about 3 minutes, until the mixture has reduced to 1/3 of a cup. Turn off the heat and whisk in the dijon mustard.

Meanwhile, slice the pork tenderloin into 8 equal pieces. Place four of the pieces between two pieces of plastic wrap and pound until they are about 1/2" to 1/4" thick.

Heat one teaspoon of the vegetable oil in a nonstick skillet over medium-high heat. Season the pounded-out pork pieces with salt, pepper, and garlic powder. Once the oil is hot (3 minutes or so), add the pork pieces and cook for about 90 seconds per side. Test with a meat thermometer to ensure the internal temperature is at least 145° Fahrenheit. Set aside on a plate.

Pound out and season the remaining four pork pieces. Add another teaspoon of oil to the pan and cook the pork for 90 seconds per side. Again, test with a meat thermometer to ensure the internal temperature is at least 145° Fahrenheit.

Return the rest of the cooked pork to the pan.

Pour in the maple-balsamic sauce and cook for 1 minute.

Garnish with scallions.