Preheat oven to 325 degrees F (160 degrees C).
In a microwave-safe mixing bowl, melt Unsalted Butter (3/4 cup) in the Panasonic Microwave Oven for 10-20 seconds. Allow it to cool slightly. Add Brown Sugar (1 cup) and Granulated Sugar (1/2 cup) and beat on medium speed for about a minute until well blended.
Add the Large Egg (1), Egg Yolk, and Vanilla Extract (2 teaspoon) and beat until fully incorporated.
Mix the All-Purpose Flour (2 1/8 cup), Salt (1/2 teaspoon), and Baking Soda (1/2 teaspoon) then incorporate it into the wet ingredients.
Fold 3/4 of the Semi-Sweet Chocolate Chips (9 ounce) into the batter. Scoop out 18 cookies, about 1/4 cup of dough for each. Place cookies on a parchment paper-lined baking sheet with plenty of room to spread.
Bake the cookies one tray at a time, for 14-18 minutes. The cookies should begin to set around the edges, be light golden brown, yet still be soft in the center. Allow cookies to cool completely.
Place the remaining Semi-Sweet Chocolate Chips (3 ounce) in a small microwave-safe bowl. Heat in the Panasonic Microwave Oven for 20 seconds, stir, then for 15 seconds. Allow the chocolate to sit for 1 minute, then stir again. If you need to, heat it for 10 more seconds.
Pour into a squeeze-it mold painter bottle fitted with a #2 round pastry tip, or a disposable pastry bag or zip top bag with the tip snipped off. Pipe on spider heads and legs around some of the larger chocolate chips. Allow to dry.
Serve with a glass of milk. Enjoy! Cooking results may vary depending on microwave oven used.