Step 1

In an ice-filled shaker, add pistachio liqueur, vodka, dry vermouth, and heavy cream and shake well to combine. If using additional simple syrup for a little more sweetness, add it here, too.

Step 2

Strain mixture into prepared martini glass.

Step 3

Combine the chopped pistachios and vodka in a jar and seal tightly. Shake to combine.

Step 4

Let mixture sit in a cool, dark spot for at least 48 hours and up to a week to infuse vodka with pistachio flavor. Give the jar a shake every now and then.

Step 5

Strain the mixture through a fine mesh sieve or cheesecloth to remove all solid particles. Stir in simple syrup.

Step 6

Mixture will likely be more brown than green, so feel free to add a little bit of green food coloring (or blue + yellow) to tint the liqueur green.

Step 7

Put water and sugar in a medium saucepan and bring mixture to a boil.

Step 8

Once boiling, lower heat and let simmer for about 10-15 minutes, until sugar is completely dissolved and mixture has thickened a bit.

Step 9

Pour syrup into a mason jar or bowl and place in fridge to cool completely before using. Syrup will continue to thicken as it cools.