Preheat oven to 350°F. Lightly grease ovenproof skillet and set aside.

In a large mixing bowl cream together butter and sugars until light and fluffy. Beat in eggs and vanilla extract until well incorporated.

In another mixing bowl stir together the flour, baking soda, salt and cornstarch.

Slowly add dry ingredient mixture to wet ingredients, mixing at low speed (I did mine in thirds). The batter will be pretty thick and smooth, but not dry and crumbly.

Crush Mini Eggs by putting in a zip lock bag and pressing/rolling down with a rolling pin. Add into cookie dough and mix at low speed until evenly distributed throughout the dough.

Transfer dough into prepared skillet, making sure it is evenly spread. If you like you can place extra (uncrushed) Mini Eggs around the top at this point.

Bake for 30-35 minutes. If you like a crispier cookie you can increase the cooking time to 40 minutes, but keep an eye on it so that it doesn't burn.

Cool for at least 15-20 minutes or it may crumble when lifting out of the skillet. Slice into triangles (like a cake or pie) for larger servings or cut into squares. Serve on its own or with a scoop of ice cream!