Combine butter and corn syrup in the bowl of a stand mixer, or medium bowl if using a hand mixer.
Add 2 cups powdered sugar and mint extract and mix on low until well combined.
Stir in another cup of powdered sugar.
Turn bowl onto a cutting board sprinkled with last cup of powdered sugar.
Knead the mixture until sugar is absorbed and is completely smooth.
Use a small cookie scoop or tablespoon to form uniform balls, and lay out on wax paper.
Heat the white chocolate in a microwave safe bowl or measuring cup, for 1 minute on 50% power, and stir. Continue heating in 15 second increments until chocolate is melted. Don’t overheat or the chocolate will burn!
Using your pumpkin mold, pour just enough of the melted chocolate into the bottom of each mold to cover the bottom and come up no more than a ¼-inch, but 1/8-inch would work perfectly. Stick your mold in the fridge for a few minutes to speed up the hardening process.
Once hardened, remove from fridge and place one mint ball in the center of each and press down to flatten out. Leave room around the edge for the top layer of chocolate to go down to “seal” the patty.
Pour another layer of chocolate over the top of each mold, then gently tap the mold on the counter to smooth out the top. Return to fridge to harden, then gently turn each patty out onto wax paper.
Repeat the process until all of the mint balls are used!