In bowl, mash together egg with avocado until well blended to desired consistency. Stir in lemon juice.
On one of the slices of bread, arrange slice of ham. Top with "green egg" mixture; cover with remaining slice of bread.
With serrated knife, slice into quarters and serve.
Per serving: about 230 calories, 18 g protein, 19 g total fat, 3.3 g saturated fat, 30 g carbohydrates, 7 g fibre, 220 mg cholesterol, 520 mg sodium % RDI: 4% calcium, 20% iron, 6% vitamin A, 20% vitamin C