In a medium skillet, cook onion in 1 tablespoon hot butter over medium heat for 4 to 5 minutes or until tender, but not brown. Add wine. Cook and stir 1 to 2 minutes or until wine is almost evaporated. In a large mixing bowl, beat cream cheese with an electric mixer for 1 minute. Add the onion mixture, Stilton cheese, half-and-half, egg, lemon peel and juice, chives, herbs de Provence, and garlic. Beat until combined. Fold in trout and 1/3 cup smoked cheddar cheese.