Nutella Truffle Cups

10 chocolate sandwich cookies
1 cup roasted, unsalted cashews
1/2 cup confectioners' sugar, divided
3/4 cup (1 1/2 sticks) unsalted butter, softened and divided
1 cup Nutella nonstick cooking spray

To make Nutella Truffle Cups: Line 2 mini-size muffin pans (12 count each) with mini baking cup paper liners, and spray with nonstick cooking spray.

Put sandwich cookies in food processor fitted with metal blade. Pulse until finely ground, about 30 seconds (yields 1 cup crumbs). Alternatively, place cookies in resealable bag and crush to fine powder with rolling pin. Sprinkle each cupcake liner with 1/2 tablespoon cookie crumbs, gently pressing against cup sides with spoon to slightly adhere.

Nutty truffle paste: Wipe out food processor and fill with cashews and 1/4 cup confectioners sugar. Pulse until finely ground (about 30 to 45 seconds). Scrape down food processor sides with rubber spatula; add 4 tablespoons butter and pur