Preheat oven to 350℉
Line an 8" by 8" cake pan with parchment paper
In a large bowl, beat melted butter and sugars together until smooth.
Beat in egg, milk, and vanilla extract.
Add flour and baking soda, stirring until combined.
Fold in the Mini Eggs and chocolate chips.
Spread evenly into the prepared pan.
Bake in preheated oven for 30 minutes or until the centre is just cooked.
Cool in pan for 15 minutes.
Using the parchment paper, lift the cookie bars out of the pan.
Allow to fully cool on a cooling rack before cutting into squares.
Store in an air-tight container at room temperature for up to 3 days.