Place 2 oz Amaretto in a shaker filled with ice. Add the juice of one lemon, that's right, all the juice you can get out of the damned thing. And for god's sake, use a REAL lemon, not that bitter and stale bottled juice, (It helps if you "roll" the lemon on a counter top using some pressure to release the juice from the membranes inside the lemon.)Shake vigorously until the shaker is frosty and your hands hurt from the cold. Strain into a martini glass, and garnish with lemon zest. MMmmmm. Puckerful!