Melt the milk and dark couverture in the oven at 88°F/31.1°C, or use tempered couverture.
In a bowl, blend the butter by hand with a spatula until smooth.
Mix the milk and dark couvertures and the butter together with a spatula or in a stand mixer fitted with the paddle attachment. The closer the temperatures of the butter and the couvertures, the easier it will be to blend them together. Stir to a smooth consistency.
Add the wine. Blend in the wine very well using a spatula or a stand mixer fitted with the paddle attachment to create a smooth ganache.
Pipe the ganache onto the chocolate discs using a pastry bag with a plain size-12 tip. If the ganache is too soft, let it set before piping. If the ganache is too cold, it can be warmed in a water bath or stirred. Stirring will aerate the ganache, leaving a lighter mouthfeel.
Allow the piped ganache to set 1 hour at room temperature.
Once the ganache is fully crystallized, dip the pieces in the dark couverture using a dipping fork. Let the couverture completely set.
Store in an airtight container at 57° to 61°F/13.9° to 16.1°C in a dark, dry place.