Add the butter and sugars to the bowl of a stand mixer fitted with the paddle attachment. Cream the butter and sugars together, about 3 minutes.
While the butter and sugars are beating, sift the flour, salt and baking soda into a separate bowl.
Add the milk and vanilla to the mixer and beat on low speed until combined. Add the dry ingredients to the mixer and beat on low speed to combine. Add the walnuts and stir to combine.
Line a baking sheet with parchment paper. Scoop 12 balls with a 1-ounce cookie scoop and put on the sheet. Freeze for 15 minutes.
Put 2 parts black melting chocolate disks to 1 part white in a double boiler and stir to melt completely. Remove from the heat and let cool slightly before dipping the pops.
Dip the end of a lollipop stick into the melted chocolate and insert into the center of a cookie ball. Repeat with the remaining sticks and cookie balls. Place back into the freezer for 15 minutes.
Use the wide end of a pastry tip to cut a crescent moon shape from 24 blue melting chocolate disks. Attach it with the curve up on the front of the cookie pop with a dot of melted chocolate to form the trunk. Attach the marshmallows to the bottom of the pop for feet. Put back into the freezer for 10 minutes to set.
Dip the entire pop into the melted chocolate to cover and coat. Let the excess drip over a bowl. Stick each pop into a floral foam to hold while you dip the remaining cookie pops. Place into the refrigerator if needed to set the chocolate. Attach blue candy melt disks to the sides of the pop for ears and use confetti sprinkles for eyes. Dot each eye in the center with an edible marker to make a pupil. Add a mouth and nose with the edible marker. Keep the pops in the refrigerator until ready to serve.