Combine amaretto, molasses, allspice, and pumpkin pie spice in a small saucepan over medium heat and cook until molasses is melted. Remove from heat and allow to cool briefly, 5 to 10 minutes

Fill a cocktail shaker with ice and add vodka, Irish cream liqueur, and amaretto mixture. Shake well to blend and strain into a cocktail glass. Serve with gingersnap cookies.