Preheat oven to 400ºF.
Place the pork tenderloins onto a baking sheet and rub each of them with a small drizzle of EVOO. Sprinkle the fennel seeds, grill seasoning and red pepper flakes evenly over both tenderloins and give 'em a rub down to evenly coat them with the seasonings. Transfer to the oven and roast about 20 minutes.
When the pork has about 10 minutes of cooking time left, place the potatoes into a large pot and cover them with cold water. Place the pot over high heat and bring it up to a bubble. Simmer the potatoes until they're tender, about 10 minutes.