Preheat your oven to 350°F (175°C). Greasing the pan will ensure that your cookie bars come out easily.
Line an 8x8 inch baking pan with parchment paper, leaving some overhang on the sides to help lift the bars out later.
In a large mixing bowl, cream together the softened unsalted butter, granulated sugar, and packed light brown sugar until the mixture is light and fluffy.
Mix in the large egg and pure vanilla extract until fully incorporated.
In a separate bowl, whisk together the all-purpose flour, vanilla pudding mix, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.
Gently fold in the Nestlé Toll House DelightFulls Dark Chocolate Morsels with Mint Filling, ensuring they are evenly distributed throughout the dough.
Spread the cookie dough evenly into the prepared baking pan. Use a spatula to smooth the top.
Bake in the preheated oven for 25-30 minutes, or until the edges are golden and a toothpick inserted in the center comes out clean.
Allow the bars to cool in the pan for about 10 minutes, then use the parchment overhang to lift them out onto a cutting board. Let them cool completely before cutting into squares.