Serves: Makes about 24 cookies, and about 4 cups ice cream
For the Classic Chocolate Chip Cookies
Cream the butter with the brown sugar and granulated sugar together well. Beat in the egg and the vanilla.
In a separate bowl, sift the flour with the cornstarch, baking soda and salt. Add this to the butter mixture and stir until blended. Stir in the chocolate chips and pecans (if using).
Using a small ice cream scoop or a tablespoon, scoop spoonfuls of dough (about 2 Tbsp) shape them into a ball and place onto a parchment lined baking tray or a plate. Chill the scooped cookies for at least an hour, or once chilled, the cookies can be frozen for baking later.
Preheat the oven to 325 F. Arrange the chilled scooped cookies onto parchment-lined baking trays, leaving 3 inches between the cookies. Bake for 15-18 minutes, until browned around the edges. Cool the cookies on the baking tray. If baking cookie dough that has been frozen, arrange the frozen cookies on the baking tray and let them thaw for 20 minutes at room temperature before baking as above.
For the Chocolate Ice Cream
For the ice cream, bring the milk and 1/2 cup of the whipping cream to a simmer in a medium saucepot. Pour this over the chopped chocolate and gently whisk until the chocolate has melted.
In a separate bowl, whisk the egg yolks and sugar. Slowly add the cream to the eggs yolks, whisking constantly. Return the entire mixture to the saucepot and stir with a wooden spoon, cooking over medium heat until you can draw a line through the custard on the spoon, about 3 minutes. Strain the custard and stir in the remaining 1 cup of whipping cream. Cover and chill the custard completely.
Pour the chilled custard into an ice cream maker and freeze following manufacturer instructions. Scrape the soft ice cream into a dish, cover and freeze until firm.
The ice cream can be made up to a week in advance and stored frozen.
To assemble, sandwich a generous scoop of the ice cream between two cookies and gently press. Enjoy immediately.