Prepare a jelly roll pan with parchment paper, leaving enough hanging over the sides for easy removal later. In the bowl of a stand mixer, or by hand, beat together the butter, peanut butter, sugar, and vanilla until smooth.
Place the cut-outs onto a new sheet of parchment paper and place them back into the freezer. Gather the remaining peanut butter mixture and press it back into the flat sheet to cut out additional shapes.
Place chocolate chips in a heatproof bowl with the shortening. Heat in 30-second increments, stirring in between until the chocolate is mostly melted. Chocolate will continue to melt in its own residual heat. Stir until completely smooth and it drizzles easily.
Remove just one or two chilled peanut butter hearts from the freezer at a time. Use a fork to dip the heart into the melted chocolate and flip it to coat both sides. Lift from the chocolate, allowing the excess to drip off. Place the dipped heart onto a sheet of parchment paper.
Heat white chocolate chips and teaspoon of shortening, working in 15-30 second bursts, until melted and smooth. – Transfer to a piping bag. Drizzle chocolate in large sweeps over the hearts to add accent drizzle. Immediately sprinkle with heart sprinkles if desired. –