You will need 16 toothpicks for assembling the sandwiches.
1 avocado, peeled and pitted
1 Tbsp. mayonnaise
3 Tbsp. chopped fresh basil
1 Tbsp. chopped fresh tarragon
1 Tbsp. lemon juice
Salt and pepper
8 slices sourdough bread, lightly toasted
4 leaves butter or bibb lettuce
12 slices cooked bacon, halved crosswise
1/4 English cucumber, sliced thin
8 slices Swiss cheese
8 slices oven-roasted turkey from the deli
1 cup alfalfa sprouts