"While attending a mixology class, I learned how to make different simple syrups, including celery-flavored. This in turn lead to playing with different ingredients and alas, the Zesty Celery Sour was born! Don't be fooled by the celery - it might sound weird, but it surprises everyone that tries it! I developed the recipe using pickled jalapenos, however I have since made it with fresh and it's equally as tasty. This will make enough simple syrup for several drinks."
Place celery, celery seed, and salt in a food processor. Pulse several times until completely blended. Press mixture through a fine mesh strainer with the back of a wooden spoon into a bowl; you will be left with about 1/2 cup of liquid.
Place celery liquid and sugar in a small saucepan over medium heat. Stir until sugar is completely dissolved, about 3 minutes. Remove from heat. Refrigerate until needed.
Place ice, vodka, 3/4 fluid ounce celery simple syrup, lemon juice, and 2 jalapeno slices in a cocktail shaker. Shake for 30 seconds; strain into an ice-filled cocktail tumbler. Garnish with remaining jalapeno slice.