In a blender container or food processor bowl combine soup, green onion, nutmeg, and pepper. Add spinach leaves, a few at a time, while blending or processing until mixture is nearly smooth.
Pour into a medium saucepan. Stir in evaporated milk. Bring to boiling. Reduce heat; simmer, uncovered, for 2 minutes, stirring occasionally. Serve soup in bowls and garnish with carrot cutouts, if desired. Makes 4 side-dish servings.