Make the Crust:

1. Preheat the oven to 350ºF.
2. Mix together pretzel crumbs, melted butter and sugar in a bowl. The mixture should be moist enough that when you squeeze it, it forms a clump, but not so wet that it sticks to your hands. See note below for troubleshooting. 
3. Pour the crumbs into a 9” pie plate and start pressing the ingredients up the sides of the pie plate to form the edges first. Once the edges are formed, work the crumbs down to evenly distribute into the bottom of the pie plate and stamp it down.
4. Bake in the preheated oven for 10-12 minutes, until lightly golden and fragrant.

Make and Bake the Filling:

1. Place pistachios in a food processor and pulse until they are finely ground, about 10 pulses. Set aside.
2. Add mascarpone and sugar to a large bowl and whisk together until smooth. Add in eggs, milk, almond extract and ground pistachios and whisk together until smooth.
3. Pour into the prepared pretzel crust and bake for 45-55 minutes, or until the outer 2-1/2” of the pie is set and puffed, and the center is still slightly wobbly. The edges may be golden.
4. Let cool almost completely on a rack before placing in the refrigerator to set overnight, or at least 8 hours.
5. Garnish the top of the pie with additional pistachio, and piped whipped cream, if desired, and serve cold. Pie will keep for 2-3 days in the refrigerator.