Preheat the oven to 350 F. In a medium bowl, whisk together flour, salt, and baking soda. In a large bowl, combine butter with both granulated and brown sugar until fluffy.
Add in the egg and vanilla extract, and mix until smooth. Add in the flour mixture, mix until it is fully combined. Fold in the chocolate chips and mini cadbury eggs.
Roll the cookie dough into balls, and place them onto a large ungreased baking sheet at least 2-inches apart. Bake for 10-12 minutes.