Heat a large, heavy skillet over medium-high heat until very hot. Rub pork tenderloin with olive oil and season generously with salt and pepper. Add pork to pan and cook, turning often, until evenly browned, about 14 minutes total. Transfer to a cutting board to rest. (Reserve skillet.)
Meanwhile, in a medium bowl, stir together remaining 1 tablespoon oil and 1 teaspoon vinegar; toss with rice, mint and almonds. Season rice salad with salt and pepper.
Add 1 tablespoon olive oil and onion to reserved skillet. Cook, stirring release browned bits from bottom of pan, until onion is tender, about 4 minutes. Stir in cherries, remaining vinegar and mustard to skillet.
To serve, slice tenderloin into 1-inch pieces. Divide rice salad among plates and serve topped with tenderloin and cherry mostarda.
Before her diagnosis, Caroline wrote a book on cakes called Cake Magic!. She started developing a birthday cake using her gluten-free mix found in that book. Check out other recipes she’s developing for her new life—and the stories behind them—on her blog, The Wright Recipes. Her next book, Catalan Food, written with chef Daniel Olivella, comes out in early September from Clarkson Potter.