Pour the coconut milk into a bowl and whisk to mix the coconut cream and water* then measure the amount needed into a small saucepan and heat over medium until just simmering.
250 ml (1 cup) full-fat canned coconut milk
While the milk is heating, finely chop the chocolate and place it into a heat-proof bowl.
200 grams (7 oz.) dark chocolate
Once the milk is hot, pour it over the chopped chocolate into the bowl. Let this rest for two minutes, then whisk until fully combined. Whisk gently to start with and be sure to mix until fully combined - it might take longer than you think.
Add the vanilla and whisk again to incorporate. You can place a piece of parchment paper directly onto the ganache now, but I never do this (there is a possibility of it forming a skin, but in my experience it only happens very rarely).
1 teaspoon vanilla extract
Cool the ganache to room temperature. It should be solid enough at room temperature to spread onto a cake, but can be refrigerated if not. Use your judgement here for whether the ganache needs to be chilled or not depending on how you plan to use it.
When the ganache is fully cooled, it should be solid but not hard. Use to ice cakes, top cookies, or however you'd like. To fill tarts, etc. it should be poured into the crust while still liquid and then set.
Notes
If your ganache is splitting - if it's very shiny and greasy, or very clearly split - you can usually save it by blending with an immersion blender until it comes together. This happens more often with vegan ganache because of the coconut milk but it will be fixed 99% of the time with a good blend.If the coconut milk sloshes around in the can when you shake it, you can just give the can a really good shake to combine the cream and water before measuring it. A square of baking chocolate is one ounce and a typical chocolate bar (for baking) is 100g. If using chocolate chips, this is about 1 ½ cups of chocolate.This makes about 1 ¾ cups ganache, enough for a batch of cupcakes or a single-layer cake.Storage: this will keep, in a sealed container, for up to a week in the refrigerator.Freezing: transfer the cooled ganache to an airtight container and freeze for up to three months. Thaw in the refrigerator. If there is any separation, beat with an electric mixer.