Preheat the oven to 400° F.

In a bowl, combine the trout, scallions, and half of the lemon zest. Set aside. Sift the flour and baking powder into the mixing bowl. Cut the butter into bits and rub it into the flour by hand or with an electric mixer. Combine the eggs, cream, and the remaining zest and mix into the flour mixture. Do not overmix.

Divide the dough in half. On a lightly floured surface, roll out each portion of dough 1/3-inch thick. Cut one piece of dough into triangles that measure 3 inches a side. Place 1 tablespoon of the trout mixture in the center of each triangle. Paint the edges of each triangle with the egg wash. Cut the remaining dough into triangles. Top each of the filled triangles with dough and crimp the edges with a fork. Brush the top of each scone with the egg wash. Place the scones 2 inches apart on one or two baking sheets and bake for 15 to 20 minutes, or until golden.