Step 1

Place the flour, cocoa powder and light brown sugar in a food processor. Blend briefly to combine.

Step 2

Add the coconut oil to the food processor and blend until  the mixture looks even and sandy.

Step 3

With the mixer running on low, add the water one tablespoon at a time until a ball of dough forms (you may not need to add all the water, mine took 4 tbsp).

Step 4

Remove the dough from the food processor and pat into a rough rectangle. Wrap in reusable wrap and place in the fridge to chill for 30 minutes.

Step 5

Once chilled, remove the dough from the fridge and lightly flour a clean surface. Roll out the dough with a rolling pin to a large flat circle, around 1/2cm thick.

Step 6

Use a 7-9cm circular cookie cutter to cut out as many cookies as you can. Cut a 3cm notch out of the cookie to make sure it can slide onto the rim of your hot chocolate cup.

Step 7

Transfer the cookies to a baking sheet lined with greaseproof paper and place them back in the fridge to chill for 30 minutes. Meanwhile, preheat the oven to 170c.

Step 8

Once chilled, bake the cookies at 170c for 15 mins. If the cookies lose their notch while baking, cut it out again while the cookies are still warm from the oven.

Step 9

Allow to cool fully on a wire cooling rack.

Step 10

Place 175 ml water in a medium saucepan and bring to the boil. Whisk in the cocoa powder well until smooth.

Step 11

Immediately add the plant milk and bring the temperature back to a simmer (do not let it boil).

Step 12

Once simmering, add the chocolate, and sugar. Whisking constantly, allow to simmer until completely smooth and the chocolate is completely melted.

Step 13

Remove from the heat and cover with a lid while you make the marshmallow rim.

Step 14

Thoroughly clean the bowl of a stand mixer, fitted with the whisk attachment.

Step 15

Place the aquafaba into the bowl and whip on medium speed until light and frothy. Stop the whisk, add the cream of tartar and continue whipping for around 10 minutes or until stiff peaks form. Stop the mixer.

Step 16

Place the caster sugar and water in a saucepan and mix well until the sugar begins to dissolve and forms a paste.

Step 17

Place the saucepan over medium heat and bring the mixture to a simmer. Do not sit the mixture.

Step 18

Use a candy thermometer to bring the temperature of the sugar syrup to 115c.

Step 19

Remove the syrup from the heat. Turn the stand mixer to a low speed and very carefully drizzle the sugar syrup into the whipped aquafaba, while the mixer runs.

Step 20

Once fully incorporated, stop the mixer. If the marshmallow fluff appears too runny, place the mixing bowl in the fridge for 10-20 minutes to chill then whip again until more stiff. Transfer the marshmallow fluff to a piping bag fitted with the widest nozzle you have access to.

Step 21

Divide the hot chocolate into mugs. Carefully pipe the marshmallow fluff around the rim of the mug or directly onto the top of the hot chocolate. (Optional) Use a chef's blowtorch to scorch the marshmallow topping lightly. Slot a shortbread cookie onto the side of the mug and serve.