Place the powdered sugar, peanut butter, butter and 2 tablespoons of water in the bowl of a mixer.
Beat on low speed until a dough forms. If the dough is too crumbly to hold together, add more water, 1 teaspoon at a time, until desired consistency is reached.
Line an 8" or 9" square pan with foil. Coat the foil with cooking spray.
Press the peanut butter mixture into an even layer in the pan, then chill for 30 minutes.
Remove the peanut butter mixture from the pan by using the edges of the foil as handles and cut out egg shapes with a cookie cutter.
Place the eggs on a parchment lined sheet pan and freeze for 30 minutes.
Add the chocolate chips and shortening to a microwave safe bowl. Microwave in 30 second increments until chocolate is melted. Stir until smooth.
Remove the eggs from the freezer and dip them in the chocolate. Tap against the side of the bowl to remove excess chocolate.
Place the dipped eggs back onto the parchment lined sheet. Repeat until all eggs are coated. Drizzle and remaining chocolate over the top of the eggs using a small spoon or piping bag.
Let sit until chocolate is firm, then serve. Eggs may be stored in an airtight container for up to 5 days.