1. Preheat oven to 325 F and thoroughly grease a 10″ oven-safe skillet (see text above for different sized skillets).
2. In a large bowl, whisk together the flour, baking soda, cornstarch and salt. Set aside.
3. In the bowl of a stand mixer or in a separate bowl with a hand mixer, cream together the butter and both sugars on medium speed until light and fluffy. Beat in the eggs, one at a time, followed by the vanilla. Scrape the bowl as necessary to ensure all of the ingredients are completely mixed.
4. Keeping the mixer running at low speed, slowly add in the dry ingredients until all of the ingredients are incorporated and a soft dough has formed. Using a rubber spatula or spoon, fold in the crushed mini eggs.
5. Spread the cookie dough evenly into the skillet, topping with more mini eggs if desired.
6. Bake for 30-35 minutes, or until the edges are light brown. Remove the skillet from the oven and allow it to cool for a few minutes, before serving with multiple spoons or cutting into wedges. Top with ice cream and salted caramel sauce if desired.

Leftovers (if there are any) can be stored at room temperature, tightly covered, for 2-3 days or in the refrigerator for up to 5 days.