Preheat the oven to 180°C, fan 160°C, gas 4. Lightly grease 2 large baking trays (or line them with baking parchment).
Put the butter and sugar in a bowl. Add the lemon extract and beat together with a wooden spoon until pale. Tip the flour into the bowl then mix it all together – it’s easy and fun for toddlers to use their hands for this stage.
Mould the mixture into 28 small walnut-size balls. They don't need to be perfect.
Arrange on the baking trays – leaving enough space between to allow them to spread – and bake for 6-7 mins until golden. Keep an eye on them as you don’t want them to go brown. Cool on the tray then transfer to a cooling rack.
To make the strawberry cream filling, wash and hull the strawberries and put in a bowl.
Add the soft butter, icing sugar and lemon extract (if using) to the strawberries and beat together with a wooden spoon. You may need to add more icing sugar (depending on how juicy your strawberries are).
Spoon a little cream on the base of a biscuit and sandwich with another. They’ll keep in an airtight container for up to a week.