Canned mango pulp works better in these frozen ice pops than fresh mangoes because of its concentrated flavor, which helps cut through the rich cashews and sweetened condensed milk. Use leftover pulp in the Spicy Mango-Mint Chutney.
Place cashews in a small bowl; add water to cover by 1 inch. Refrigerate at least 8 hours or up to overnight. Drain; discard soaking liquid. Set cashews aside.
Cook milk, mint, and cardamom seeds in a small saucepan over low, stirring occasionally, until mixture just comes to a simmer. Remove from heat; let steep, uncovered, 15 minutes. Transfer mixture to a blender; add drained cashews. Process until gritty but mostly smooth, about 30 seconds.
Place saffron threads in a liquid measuring cup; place a fine wire-mesh strainer over cup. Pour warm milk mixture through strainer to measure 3/4 cup liquid, pressing on solids to extract liquid. (If mixture yields less than 3/4 cup, add condensed milk as needed to total 3/4 cup.) Discard solids. Whisk together mango pulp, condensed milk, heavy cream, salt, and saffron-milk mixture in a bowl until thoroughly combined. (There should be about 2 cups total.)
Divide mango mixture evenly among 6 (3-ounce) ice pop molds; sprinkle with pistachios. Insert 1 craft stick into each pop. Freeze at least 8 hours or up to overnight. To serve, rinse ice pop molds under cold water to release pops from molds.
Ice pops may be frozen in molds up to 2 weeks.
Canned mango pulp is available at Indian markets or online.