Prepare 3 pieces of parchment to fit rimmed cookie sheet. Place one in pan and set aside. Preheat oven to 350°. Place all ingredients except cacao nibs in a small pan over med heat. Whisk until melted, increase heat and bring to a rolling boil, for 1 min. After 1 min (or when kitchen/candy thermometer reaches 224°), remove from heat, add cacao nibs and stir. Cool 5-10 min, stirring occasionally.
Drop mixture onto parchment-lined pan, 1/2 to 1 t at a time, leaving 4 inches between each (max 8 pieces per sheet). Cookies will spread while baking. Bake 5 min; rotate and bake 3-4 min, until large air bubbles have subsided and some small holes appear. Remove from oven; gently slide parchment onto counter; let cool until firm. Place new parchment sheet onto pan, then repeat dropping and baking steps. Once cooled, carefully transfer cookies to airtight container and store. Can be made 2 days ahead. Makes 2 to 2 1/2 dozen, depending on size.
In mixer bowl, whip cream on med-high until soft peaks barely form and still appear wet and shiny, 3 min. Reserve 3/4 c of whipped cream in separate bowl (for garnish); chill both bowls.
In a small pot, add milk and espresso; heat until small bubbles appear on edges of pan; do not boil. Whisk to dissolve espresso; remove from heat. Add chocolate; cover pan and let melt (5 min). Using spatula, scrape bottom and mix until smooth.
Add 1/2 c chilled whipped cream to melted chocolate. Mix well. Pour chocolate mixture into remaining whipped cream bowl and fold until fully combined. Divide between 4 cups, then refrigerate; cover cups with plastic wrap after one hour. Refrigerate a total of 4 hr or overnight.
When ready to serve, lightly whisk reserved whipped cream until soft peaks form, then dollop into each cup to resemble frothed milk. Garnish with Cacao Nib Lace and serve.
* You can substitute chopped, raw nuts (such as pecans) for the cacao nibs. Do not use roasted nuts, as they might burn.
** Callebaut Milk Chocolate is available in your Market Bakery retail section.