Preheat the oven to 180°C (gas mark 4, 350°F) and line a baking tray with parchment paper.
Add butter and caster sugar into a large mixing bowl and cream together until light and fluffy. You can do this by hand or use an electric whisk to cream the ingredients together quickly.
Add an egg and a teaspoon of vanilla into the mixing bowl and mix together until evenly combined.
Pour the plain flour into the bowl and mix together until the biscuit dough has formed. Use your hands to bring the dough together. Add a tablespoon of water If the mixture is too dry and is not coming together.
Lightly sprinkle flour on your work-surface and knead the dough until it comes together.
Roll the dough quite thin, so that it has a thickness of 3mm to 5mm, use a crinkled edge cookie cutter to cut out the biscuits. Then place them on a lined baking tray leaving a gap between each piece.
Bake the biscuits in a preheated oven for 10 to 12 minutes or until the biscuits start to brown around the edges. Place the biscuits on a cooling rack for it to cool down completely.
Once the biscuits have cooled down, mix together water and icing sugar until a thick icing mixture has formed. The icing should be thick enough to spread and not running off the edges.
To assemble the empire biscuits, spread jam on top of one biscuit and top with another biscuit. Then gently spoon (or pipe) icing on top of the biscuit, leaving a border around the edges.
Top with a glacé cherry centred in the middle. Leave the icing to harden and then enjoy!