01 -  Place pistachios in a bowl and cover with water. Soak overnight or for 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. Blend until completely smooth. 
 03 -  Pour the blended mixture through a nut milk bag or fine mesh sieve into a pitcher. Discard solids or reserve for baking. 
 04 -  Transfer pistachio milk into a saucepan and warm over medium heat, whisking until hot but not boiling. Sweeten to taste if desired. 
 05 -  Brew espresso or strong brewed coffee using your preferred method. 
 06 -  Pour hot pistachio milk into serving cups, reserving some froth. Add espresso to each cup and gently stir to combine. 
 07 -  Spoon remaining froth on top, garnish with crushed pistachios as desired, and serve immediately.