Preheat your oven to 350°F (175°C). Grease a 9-inch pie dish with a bit of butter or non-stick spray to ensure easy removal later.
In a large mixing bowl, combine the melted butter, light brown sugar, and granulated sugar. Whisk together until smooth and well-combined. Then add in the egg, egg yolks, and vanilla extract, whisking until fully incorporated.
In a separate bowl, whisk together the all-purpose flour, cornstarch, and salt. Gradually add this dry mixture to the wet ingredients, stirring until just combined. Be careful not to overmix.
Using a rubber spatula, gently fold in the semi-sweet chocolate chips and toffee bits until evenly distributed throughout the batter.
Transfer the cookie mixture into the prepared pie dish, spreading it evenly with the spatula.
Place the pie dish in the preheated oven and bake for 25-30 minutes, or until the edges are golden brown and the center is set but still slightly soft.
Allow the Toffee Chocolate Chip Cookie Pie to cool in the dish for at least 15 minutes before slicing. Serve warm, possibly with vanilla ice cream or whipped cream.
