Instructions:

• Step 1: Preheat your oven to 350°F (175°C).
• Step 2: Line a 9x13 inch baking pan with parchment paper or lightly grease it.
• Step 3: In a large mixing bowl, combine flour, salt, and baking soda. Whisk together until well mixed.
• Step 4: In another bowl, cream melted butter, brown sugar, and granulated sugar until light and fluffy.
• Step 5: Add egg, egg yolk, and vanilla extract to the butter-sugar mixture and mix until incorporated.
• Step 6: Gradually add the dry ingredients to the wet mixture, stirring until just combined.
• Step 7: Fold in chocolate chips until evenly distributed.
• Step 8: Spread half of the cookie dough into the prepared baking pan and bake for 12-15 minutes.
• Step 9: Let the cookie base cool completely in the pan.
• Step 10: Spread the softened ice cream evenly over the cooled cookie layer.
• Step 11: Crumble the remaining cookie dough over the ice cream layer and sprinkle with chocolate chips.
• Step 12: Cover and freeze for at least 4 hours until firm.
• Step 13: Remove from the pan, cut into squares, and serve with hot fudge sauce if desired.