01 - Place raw pistachios in a bowl, cover with water, and soak overnight or at least 6 hours. Drain and rinse thoroughly.
02 - Combine soaked pistachios, 3 cups filtered water, vanilla extract, maple syrup or honey, and a pinch of sea salt in a blender. Process until completely smooth.
03 - Pour the blended mixture through a nut milk bag or fine mesh sieve into a pitcher. Discard remaining solids or reserve for baking.
04 - Transfer pistachio milk to a saucepan and gently whisk over medium heat until heated through, being careful not to boil. Adjust sweetness as desired.
05 - Brew espresso or prepare strong coffee using an espresso machine or coffee maker.
06 - Pour hot pistachio milk into serving cups, reserving some froth. Add espresso to each cup and stir gently to combine.
07 - Top each cup with reserved froth and garnish with crushed pistachios if desired. Serve immediately.