Place eggs in a medium saucepan and cover with hot water. Bring water just to a boil over medium heat; set aside and let stand 10 minutes. Run under cold water until eggs are just cool enough to handle. Peel warm eggs and slice.
While eggs cook, finely chop trout and dill together. Transfer trout mixture to a small bowl with crème fraîche and mustard. Season to taste with salt and pepper.
Spread toast with trout. Top with radishes, egg and dill fronds. Serve with salad.
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.