Start by making the chocolate biscuits. In the bowl of a stand mixer with the paddle attachment fitted beat dairy-free butter and sugar together until creamy. Add in oil and beat for a few more minutes until the mixture starts to get pale. Add dry ingredients and continue to beat on low until a soft dough forms.
Remove dough from the bowl and place on a sheet of baking paper. Place a second sheet on top and use a rolling pin to roll out the dough until you have a rectangle shape roughly 5mm in height. Use a ruler or spatula to shape the edges of the dough in order to get a rectangular shape. Place the rolled out dough in the fridge for at least 2 hours, or the freezer for 30 mins to chill.
Preheat the oven to 180°C and line a large baking tray with baking paper.
Remove the dough from the freezer and using your ruler, cut the dough into small rectangles 2.5cm by 6 cm. If the dough starts to get too soft as you’re working with it, place it back in the fridge or freezer to firm up as this will prevent the biscuits spreading in the oven. You should end up with 24 rectangles. Place on the prepared baking tray and bake for 8-10 minutes until just firm. Let cool on the tray for 10 minutes as they continue to firm up, before transferring them to a wire rack to cool completely.
Make the malt filling. Place all of the filling ingredients into a large bowl and beat with an electric mixer or a stand mixer with a paddle attachment fitted. Mix everything together until it is creamy.
Place the filling into a piping bag and snip off the end. Pipe the mixture onto the bottom side of a biscuit, before using another to sandwich it together. You want to be able to see about ½cm of filling in each biscuit. Continue with all and then place the filled biscuits back into the freezer for another 30 minutes.
In a medium size microwave safe bowl, add the chocolate and coconut oil and melt together in 30 second burst in the microwave, stirring with a metal spoon between each time. Once there are only a few lumps left, just continue mixing with the spoon until it becomes silky smooth.
Using a fork, dunk the cold biscuits into the chocolate mixture, turning to ensure each biscuit is completely coated. Drain any excess before placing it onto another baking tray lined with baking paper. Repeat with all biscuits. Place the chocolate coated biscuits in the fridge until set.
Store the Tim Tams in an airtight container in the fridge to prevent melting for up to 7 days.