In a bowl, combine the chopped shallot, crème fraiche and lemon juice, mix to incorporate. Chill and marinate for 30 minutes or longer. As a time saver, you can add your cleaned chopped lettuce on top of the radish mixture. When you're ready to serve, season the salad with salt and pepper, toss. Garnish top of salad with shaved apple and the chopped green onion.