For the frosting, beat the butter, powdered sugar, milk and vanilla together with an electric whisk or stand mixer until smooth and thick. If necessary, add a little more powdered sugar to thicken or a little milk to thin.
Beat in a few drops of red food coloring to get a pale pink colored frosting.
Add the frosting to a piping bag with a ¼-inch round tip (such as Wilton #10).
Take an Oreo and pipe a thin layer of frosting over the top, then smooth it with a butter knife.
Pipe a line of frosting down the middle of the oreo. On each side of the line, pipe a squigly line back and forth to fill the side. Repeat with the other side.
Repeat with the remaining cookies and frosting.
Place the cookies onto a cookie sheet and place into the fridge for 15 minutes for the frosting to set.
Gently brush the cool melted raspberryjelly over the frosted ‘brains’.