Line an 8x4-inch loaf pan with plastic wrap, leaving overhang on the sides. Place the empty pan in the freezer to chill.
In a large bowl, whip the heavy cream until stiff peaks form. Gently fold in the sweetened condensed milk and vanilla extract. Divide this base evenly into three separate bowls.
Into the first bowl, fold in the chopped cherries and cherry syrup. Pour into the chilled loaf pan, smooth the top, and freeze for 45 minutes.
Into the second bowl, fold in the artisanal pistachio paste and chopped pistachios. Spread carefully over the set cherry layer and freeze for another 45 minutes.
Into the final bowl, fold in the cooled melted chocolate chunks and cocoa powder. Spread over the pistachio layer.
Wrap the overhanging plastic wrap over the top of the loaf to seal it. Freeze for at least 8 hours, or overnight, before slicing and serving.
