Cream the butter and sugars

• In a large mixing bowl, whisk the cold cubed butter until slightly creamy.
• Add the caster sugar and light brown sugar and whisk until well combined and fluffy.

Add the eggs, vanilla and chocolate

• Add the whole egg, egg yolk and vanilla extract.
• Add the chopped mini eggs and the chocolate chunks or chips.
• Whisk until fully incorporated.

Fold in the dry ingredients

• Add the flour, baking powder, baking soda and salt.
• Gently mix until just combined, without overmixing.

Preheat the oven

• Preheat the oven to 175–180 °C (350 °F).

Fill the tray

• Place the cookie dough into a square 8x8 tray and spread it evenly.

Bake the cookie bars

• Bake until the tops are lightly golden while the centres remain soft.
• If the top turns golden but the inside is still very raw, cover loosely with foil and continue baking.

Cool and serve

• Remove from the oven and let cool slightly.
• Serve warm with ice cream.