To make the filling, place the ground almonds and sugar in a food processor. Process until well combined. Add the almond extract, rose water, espresso powder and almond milk. Process again until the mixture comes together. Divide the mixture into 20 equal parts (each will be about ½ ounce [30 g]) and shape into balls, then set aside on a plate.
Line a wide tray with parchment paper and set aside.
Prepare a double boiler. To do this, place a pot half filled with water on the stove and bring to a boil on a medium heat. On top of the pot, set a clean, heatproof bowl large enough so it does not touch the boiling water. (This technique is also called bain-marie, and it is used for transmitting a gentle heat. I recommend using it when melting chocolate as this ingredient can easily burn on high temperatures.)
Place the chocolate in the bowl and add the coconut oil. Mix well to combine and let the chocolate melt, then remove it from the heat and let it sit for 5 minutes.
Using a fork, dip each marzipan ball into the melted chocolate. Transfer them to the parchment-lined tray and refrigerate for 30 minutes.
These marzipan truffles will keep well for up to 4 weeks, stored in an airtight container and refrigerated.