Smoked trout & apple salad with polenta croutons

Polenta, instant	2 cups
Butter, unsalted	4 tablespoons
Parmesan, grated	2/3 cup
Grapeseed oil	2 tablespoons
Apples, small Gala or Fuji, cored, thinly sliced	2
Trout, smoked, skinned, boned, fork flaked	½ pound
Mâche	4 cups
Walnuts, coarsely chopped	¾ cup
Mayonnaise	¼ cup
Lemon juice, fresh	1 tablespoon
Salt
Pepper, freshly ground
Chives, minced	2 tablespoons

1. Cook the polenta according to its package. 
2. Remove from heat, and vigorously stir in the butter and cheese until evenly distributed. 
3. Quickly rinse a 12-by-17-inch rimmed baking sheet with cold water, and shake it dry. 
4. Immediately mound the polenta in the pan and, working quickly and using a spatula repeatedly dipped in hot water, spread the polenta in an even layer about ½-inch thick. 
5. Cover with a kitchen towel, and let stand for at least 1 hour at room temperature. 
6. Cut into ½-inch cubes. In a frying pan over medium-high heat, warm the oil. 
7. Add the polenta cubes, in batches as needed to avoid crowding, and sauté until lightly browned on all sides; transfer to paper towels to drain. 
8. Arrange the apples on a platter. 
9. Scatter the trout, greens, walnuts, and polenta croutons on top. 
10. In a small bowl, stir together the mayonnaise, juice, salt, and pepper. 
11. Drizzle over the salad, sprinkle with chives, add a grinding of pepper, and serve. 

Recipe from Williams-Sonoma Salad of the Day by Georgeanne Brennan.