Preheat oven 180 degrees C
Sieve the flour and sugar into a large bowl and mix well together. Add in the oat milk and oil and fold the batter together until well combined but not over mixed.
Line a baking tray approx 23 x 35cm x 5 cm with baking parchment and add the batter and level it out. Bake for 9 mins with regular self raising flour but if using gluten free bake for approx 14 mins until you insert a wooden skewer and it comes out dry.
Add the plant based cream to a large bowl along with the icing sugar and scrap out the inside of the vanilla pod and add. Using an electric whisk whip the cream until you reach stiff peaks, this should take 3-4 mins. Add in the vegan cream cheese and whip again until it's all well combined and super smooth with stiff peaks. You want to ensure its thick enough so that it will hold its shape.
Sieve in the 2 tbsp of icing sugar to the coffee and add in the marsala or coffee liquor if using and mix well.
Get the plate you want to serve the tiramisu from and cut the sponge in half. Put a sheet of baking parchment on top of the base and flip it over and remove the bottom baking paper this will be easier to transfer. Carefully transfer half of the sponge to the plate.
Gently pour over half the coffee mixture onto the sponge and use a pastry brush to ensure you have covered the sponge evenly. Add on top half the cream and spread it out so that the sponge is well covered.
Sieve over some cocoa powder on top.
Next carefully add on the remaining half of the sponge and try to line it up so its exactly on top of the base layer. Pour over the remaining coffee mixture and spread it around with a pastry brush so its well covered. Add the remaining cream so you have a lovely generous cream layer, finish with a coating of cocoa powder and if you have any chcolate finely slice it and sprinkle it over the top!