Whip Up the Decadent Ganache: Place your chocolate chips in a medium-sized bowl. Gently warm the heavy cream in a small saucepan over low heat until it just begins to bubble around the edges. Pour the warm cream over the chocolate chips, let it rest for 30 seconds, then whisk until beautifully smooth. Stir in the vanilla and peppermint extracts. Cover with plastic wrap and chill in the refrigerator for several hours until it thickens into a pourable glaze, stirring occasionally. You can even make this the day before!
Prepare for Baking: Preheat your oven to 350°F (175°C). Line a 10x15-inch jelly roll pan with foil, then lightly spray it with cooking spray (a flour-based spray works great here).
Craft the Cake Batter: In a large mixing bowl, beat the eggs on high speed for 3 minutes until they're light, frothy, and dark yellow. Next, beat in the granulated sugar, brewed coffee (or water), and vanilla extract until fully combined. In a separate bowl, whisk together the unsweetened cocoa powder, salt, baking powder, and all-purpose flour. Gently fold these dry ingredients into your wet mixture until just blended, being careful not to overmix.
Bake the Perfect Sheet Cake: Pour the thin cake batter evenly into your prepared pan, spreading it with a spoon or spatula to cover every corner. Bake for 9-11 minutes until the edges slightly pull away from the pan and the center springs back when gently poked.
Roll with Ease: While the cake is baking, lay a clean kitchen towel flat on your countertop and generously sprinkle it with about ¼ cup of powdered sugar. Immediately after taking the cake out of the oven, carefully invert the hot pan onto the sugared towel. Gently peel off the foil. Starting from a short end, fold about half an inch of the towel over the cake's edge and carefully yet firmly roll the warm cake up into the towel. Let it cool completely in its rolled state for at least one hour.
Create the Creamy Filling: As your cake cools, prepare the filling. In an electric mixer fitted with a whisk attachment (or using a hand mixer), beat the heavy cream. Slowly add the powdered sugar, one tablespoon at a time, until stiff peaks form. Stir in ½ teaspoon of peppermint extract and taste; add up to ¼ teaspoon more if you prefer a stronger mint flavor. Finally, mix in the green food coloring until you achieve your desired minty green hue.
Assemble Your Delicious Roll: Once the cake is completely cool, carefully unroll it from the towel. Don't worry if it retains a slight curve! Spread the mint whipped cream filling evenly over the cake, leaving about an inch bare on both short ends. Sprinkle generously with mini chocolate chips or mint baking chips. Gently and carefully re-roll the cake. Wrap it snugly in plastic wrap and chill for at least one hour before frosting.
Garnish and Serve: Place your chilled cake roll on a wire rack set over a cookie sheet. Pour the thickened chocolate ganache glaze evenly over the entire cake, making sure it covers the top, sides, and ends. Transfer the glazed roll to a serving plate and garnish with additional mini chocolate chips or mint baking chips. Chill the cake for at least another hour before slicing and serving for the best results. Store any leftovers loosely covered in the refrigerator.