Steeping the Mint: Heat cream just to a simmer on the stove. Coarsely chop fresh mint and add to the warm cream. Allow mint to steep for at least 30 minutes. Mint can also be steeped in cold cream in refrigerator overnight.
Melting chocolate: Place 8 ounces white chocolate in a microwave-safe bowl. Microwave chocolate for 30 seconds then stir. Microwave again for 30 seconds and stir again. Be careful not to overheat chocolate—most of the chocolate should be melted, but there should still be a few small pieces of unmelted chocolate in the mix. Those pieces will melt out in a minute or two. Chocolate can also be melted in a bain-marie.
When chocolate is ready, strain mint from the cream and reheat. Pour cream over the white chocolate. Add several drops of peppermint extract and with a narrow spatula start mixing the cream into the chocolate by stirring in very tight circles in the center of the mixture. As chocolate begins to combine with cream, an emulsion is formed. Mixture will have consistency of mayonnaise. Continue to stir in circles and widen the circle to thoroughly incorporate all of mixture. Once mixed, ganache can be covered and placed in refrigerator until firm, approximately 1 hour.
Making Truffles: Using a small ice cream scoop, size 70 or 100, or a melon scoop, scoop ganache into balls and place on a plate. Ganache can also be scooped with a spoon and rolled by hand. Cover ganache balls with plastic wrap and return to refrigerator.
Melt 8 ounces of chocolate, again being careful not to overheat chocolate. Place a small amount of chocolate in one hand and roll a ganache ball in the chocolate to coat. Place truffle on a cookie sheet covered in plastic wrap. When all truffles are coated repeat process to add a second coat, if desired.
The truffles can be decorated with melted dark chocolate or a sprinkling of ground biscotti.
Fresh truffles last about a week at room temperature. If stored in the refrigerator, keep truffles covered with plastic wrap while they come to room temperature.
Variation: To make Cappuccino White Truffles, replace mint with 3½ teaspoons instant espresso powder, or to taste.