Once the cake has cooled, break up the cake and place in a large bowl.
Add ¼ cup frosting and mix with a hand mixer (or in a stand mixer) until the cake starts to come together.
Line an 8x8 baking pan with parchment paper (use clothespins to hold down the sides of parchment paper) and press the mix into the pan.
Use a pastry cutter (or something with a large flat edge) and press down into the pan. Then use an offset spatula to smooth the top of the cake pop mixture.
Place in the freezer for 1-2 hours until set.
Lift the sides of the parchment paper up to remove the cake pop mixture onto a clean surface.
In separate microwave safe jars, melt the candy melts. Microwave about 1 minute at 50% power. Remove to stir and return for 30 second intervals until melted. DO NOT OVER HEAT.
Cut into 20 pieces. Gently reshape the pieces to be slightly smaller, fatter rectangle. To do this, press the tops down and the sides in and work until you get your desired shape. (You want to make sure it is thicker than the sandwich cookie you’re going to stick on top).
Stick a candy stick in the melted candy and then press into the bottom of the cake pop. Take a mini sandwich cookie and add a drop of candy melts to one side of the cookie and press onto the top.
Set aside a pan lined with parchment paper. Let the candy melts set. Once they are all assembled, place in the refrigerator or freezer for another hour.
Remove from freezer. If necessary, re-melt your candy melts, but do not over heat or the consistency will change and will ruin the cake pops.
Gently dip each cake pop into the candy melts. Gently tap the side of the cup to let the access candy drip from the sides, allowing the Lego to form. Place bake on parchment paper to dry. Repeat with every cake pop. Allow to sit until candy hardens.