- 1 medium ripe California avocado (preferably Hass)
- 1 tablespoon fresh lemon juice
- 1 tablespoon fresh chives, minced
- 1/2 teaspoon kosher salt
- 1/8 teaspoon freshly ground black pepper
- 12 very thin slices white sandwich bread
- 2 tablespoons mayonnaise
- 1/2 pound purchased or premade thinly sliced rare roast beef
- In small bowl, mash avocado with fork. Stir in lemon juice, chives, salt, and pepper. Spread avocado mash over 6 slices bread, dividing evenly.
- Spread other 6 slices bread with about 1 teaspoon each mayonnaise. Top with roast beef, dividing evenly. Gently press avocado-topped bread slices, avocado sides down, onto each sandwich.
- Using long serrated knife, trim off crusts and cut each sandwich lengthwise into thirds.
- Transfer the sandwiches to a covered plastic container to transport them to the picnic, and then simply pass around the container to serve. To keep the bread from drying out, when stacking the sandwiches in the container, lay a sturdy, barely moistened paper towel between each layer and another one over the top.