01 -  Place pistachios in a bowl and cover with water. Soak overnight or for a minimum of 6 hours. Drain and rinse thoroughly. 
 02 -  Blend soaked pistachios with 3 cups filtered water, vanilla extract, maple syrup or honey, and sea salt until mixture is very smooth. 
 03 -  Pour the blended mixture through a nut milk bag or fine mesh sieve into a pitcher. Discard solids or reserve for another use. 
 04 -  Transfer pistachio milk to a saucepan. Warm gently over medium heat, whisking, until hot but not boiling. Sweeten as desired. 
 05 -  Prepare espresso or strong brewed coffee using an espresso machine or coffee maker. 
 06 -  Pour hot pistachio milk into cups, reserving some froth. Add espresso to each cup and stir gently to combine. Spoon froth over the top and garnish with crushed pistachios if desired. Serve immediately.