Sprinkle pork tenderloins with garlic salt and pepper. Allow to stand at room temperature for 30 minutes.

Preheat oven to 425 degrees F (220 degrees C).

Heat 2 tablespoons of olive oil in a saucepan over medium heat. Stir in garlic, shallots, and red pepper; cook and stir until the onions have softened and turned translucent, about 10 minutes. Add chicken stock, brandy, thyme, and rosemary. Increase heat to medium-high, and simmer until the sauce has reduced by 1/3, about 5 minutes. Remove the thyme and rosemary sprigs, and stir in the hot pepper jelly until melted; set aside.

Meanwhile, heat remaining 2 tablespoons of olive oil in a skillet over high heat until it just begins to smoke. Add pork, and cook until golden brown on all sides, about 5 minutes. Remove pork and place into a roasting pan.

Roast pork in preheated oven until a thermometer inserted into the center registers 145 degrees F (63 degrees C), about 10 minutes. Once done, place pork onto a plate and cover with foil; allow to rest for 5 minutes.

To serve, remove peppers and onions from the sauce, and spread out onto a serving platter. Slice pork diagonally into 1-inch slices and arrange over the peppers. Pour 1/2 cup of the brandy sauce over the pork, and sprinkle with 3/4 cup of Gorgonzola cheese. Serve remaining sauce and cheese in separate serving dishes on the side.