Culinary lavender lends a subtle floral sweetness to these decadent chocolate mocha truffles. Buy the best dark chocolate you can find, with 70 percent or higher cocoa percentage.
Place chocolate and butter in a heat-proof bowl; set aside.
Heat cream, espresso powder and lavender in a small pot over medium heat. Bring to a simmer then remove from heat. Let steep 10 minutes.
Bring to a simmer again, then strain cream through a fine mesh sieve into the bowl with the chocolate. Let sit 5 minutes, then whisk smooth. Pour into an 8-inch x 8-inch baking dish, cover, and chill until firm, about 2 hours.
Use a tablespoon to scoop out a truffle-size portion of chocolate and place it on a parchment paper-lined baking sheet.
To shape into balls, dip one edge in a bowl of cocoa powder. Roll the truffle in your hands until round and smooth. Dip and toss the truffle in the cocoa bowl to coat it completely. Repeat rolling and coating the remaining truffles. Store in the refrigerator.