Preheat the oven to 180°C, fan 160°C, gas 4. Line 2 baking sheets with baking the butter and sugar together in a bowl, until pale and creamy.
Sieve the flour into the bowl along with 1 tablespoon of the milk.
Mix everything together with your hands to make a ball of soft dough - you might need to add the remaining milk.
Sprinkle a little flour over a table. Divide the dough into 4 pieces and roll out 1 piece to a thickness of about 5mm. Using lettershaped cutters, help your little one cut out letters to spell 'I love mum' or another message. Repeat with the remaining dough
Using a palette knife, carefully transfer the letters to the baking sheets. Bake for 12-14 minutes until the biscuits are just golden. Leave them to cool on the baking sheets for a few minutes before putting them on a cooling rack to cool completely.
Let little ones decorate the biscuits using edible glitter writing icing and decorations. Store in an airtight container for up to 3-4 days, but be careful not to chip the icing!