Cut or tear iceberg lettuce and radicchio into small pieces. Arrange on individual serving plates.
Halve melon and discard seeds. Scoop out flesh with a melon baller. Cut grapes in half. Scatter melon balls and grapes over salad greens.
Heat butter in a nonstick pan over medium heat. Cook turkey until browned and cooked through, about 8 minutes. Season with salt and pepper. Stir in lemon thyme.
To make dressing, whisk sour cream oil and lemon juice in a bowl. Add salt and pepper to taste. Drizzle over salad greens. Top with turkey and garnish with walnuts.
health guide
Melons contain pectin, a type of soluble fibre that may help keep blood cholesterol levels in check. Melons may also help protect against cardiovascular disease and some cancers.