For the Mint Buttons: In a large bowl, combine the softened cream cheese with 1 cup of powdered sugar. Mix with a stand mixer or hand mixer until it's wonderfully smooth.
Stir in the mint extract and your green food coloring (if you're using it) until the color is evenly distributed and lovely.
Gradually add the remaining 3 ½ cups of powdered sugar, mixing until just combined. Use your hands to finish mixing the dough; it's the quickest way to get a smooth, uniform consistency.
Line a large baking sheet with parchment paper. Scoop out about a teaspoon of the dough for each button and gently roll it into a neat little ball in your palms. Place these on your prepared baking sheet.
Using the end of a wooden spoon or a small measuring spoon (dust it with a little powdered sugar if it tends to stick), make a small indentation in the center of each dough ball.
Chill your mint buttons in the refrigerator for about 1 hour until they are nice and firm.
For the Chocolate Ganache: Place the semi-sweet chocolate chips in a heat-proof bowl.
Heat the heavy whipping cream in a small saucepan until it just begins to simmer.
Pour the hot cream over the chocolate chips. Let it sit undisturbed for 2 minutes, then stir gently until the chocolate is completely melted and the mixture is silky smooth.
Transfer the ganache to a Ziploc bag. Let it cool and thicken for about 30 minutes at room temperature, or pop it in the fridge briefly (keep a close eye on it!) until it reaches a thick, yogurt-like consistency – perfect for piping.
Assemble Your Buttons: Snip a small corner off the Ziploc bag. Pipe the thickened ganache carefully into the indentations of your chilled mint buttons.
Chill for another hour, or until the ganache is fully set. Store these delightful treats in the refrigerator. Enjoy!