Line two baking sheets with grease proof paper and place to one side.
In a bowl, cream together the butter and icing sugar until pale and creamy using an electric whisk.
Whisk in the almond and vanilla extracts and 1 tablespoon of lemon juice.
In a separate bowl sift together the plain flour and cornflour then add the lemon zest.
Add the flour and cornflour mix to the butter and icing sugar in thirds. In between each third of flour/cornflour, whisk in 1 tablespoon of plant milk.
Spoon the dough into a piping bag that has been fitted with a star tipped nozzle.
Pipe 20 bunnies of equal size across the two baking sheets.
Once piped, place them into the fridge for at least 30 minutes or in the freezer for at least 15 minutes.
While the bunnies chill, pre-heat the oven to 180C / 356F /gas mark 4.
Once the bunnies have chilled, place into the centre of the oven and bake for 12-15 minutes.
Remove them from the oven once the edges have become to go golden brown.
Leave them to cool down on the trays.
In the meantime, mix the icing sugar, butter and 2 tablespoon lemon juice to make the buttercream.
As soon as the bunnies are cold, fill a second piping bag with the buttercream and pipe a small amount of buttercream on the flat side of a bunny then sandwich together with another bunny.
Repeat until all the biscuit bunnies and buttercream have been used