This is a general term for a confection of cream and chocolate, and sometimes butter, in a ratio that depends upon what you would like to use it for.
Ganache can be anywhere from quite soft and silky to stiff enough to mold by hand into shapes, although it is difficult and melty to work with.
The softest ganache, used between cake layers, will be a 1:1 ratio, by weight, of cream and chocolate, often chilled and then whipped like frosting. A stiffer one contains more chocolate, the stiffest one being 1:3 cream:chocolate and being used as a glaze, poured on while still quite warm, and allowed to harden.
We are going to make something in between.

Take a 12 ounce bag of chocolate chips and put the chips in a heatproof bowl. I like enamelled-steel camping dishes. These also make EXCELLENT makeshift double-boiler tops. The better the chips, the better the ganache. Dark or bittersweet chips from a reputable choclatier are fine. You may also get fancy and instead use a chopped-up bar of your favorite munch. White chocolate works for ganache but the ratios are different and you will have to experiment. Set your chocolate aside for the moment.

You are now going to flavor your truffles. We want a coffee flavor, but chocolate and water do NOT mix in baking or candy applications!!! So we are going to use instant coffee or espresso, dissolved in our canna cream.

Measure out 8 fluid ounces, or one cup, of the cream you have just made and place it in the HEAVIEST saucepan you own. Add 2 tablespoons of your strained cannabutter.

If you do not have a saucepan that you could bean a burglar with, do this step in your double boiler or crock pot, because you do NOT want to scorch the cream! Over very low heat on the stove, or over boiling water in your double boiler, heat the cream with enough instant coffee or espresso to make the equivalent of a pretty strong cup of coffee. Personally, I like my coffee thick and my chocolate dark and dank, so I would use nearly twice what the instant espresso package suggests. Get your cream really hot but NOT BOILING. You should see a bubble or two; stir it around constantly to avoid scorching and blend in the coffee. Now before it boils, take it off the heat and pour it over the chocolate in your heatproof bowl.

Let it rest a few moments and then start stirring it to blend the cream and melted chocolate. Stir it well.

Set it aside, in the fridge is a good place. It needs to cool and thicken.

These pics may be confusing- the whitish-green shit is some white chocolate truffle filling I made this weekend at the same time as the dark.