In a microwave safe bowl or measuring cup with a spout, melt half of the white chocolate in the microwave for 60 seconds on 50% power. Stir, and then heat in 30 second intervals on 50% power, stirring after each time, until melted. (If there are some small unmelted pieces, stir and they will melt - don't overheat or the chocolate will burn.) When melted, mix in orange gel food coloring. Start with 4 drops and add more if you want a more vibrant orange.
Pour or spoon orange mixture into each pumpkin mold, filling no more than 1/3 of the way. Place in refrigerator to harden for about 10 minutes.
Place sandwich cookies in a food processor and blend into crumbs. Set aside.
Heat remaining white chocolate same as above, but do not add food coloring. Remove pumpkin mold from fridge and pour white chocolate over the orange filling another 1/3 of the way up. You will have some left over, don't discard. Immediately top with cookie crumbs, enough to cover the surface, leaving 1/4" or so at the top. Spoon or pour another thin layer of white chocolate over the cookie crumbs. Refrigerate for at least 10 minutes so the chocolate can set.
Once hardened, gently push each of the jack-o-lanterns out of the mold and place on a serving platter, cookie side down. Serve and enjoy!