Ingredients

• 1/2 cup Unsalted Butter softened
• 1/2 cup Granulated Sugar
• 1/4 cup Packed Light Brown Sugar
• 1/2 tsp Salt
• 1 large egg
• 1 Egg Yolk
• 1 tsp Vanilla Extract
• 1-3/4 cups Unbleached White All-Purpose Flour
• 1 Tbsp Corn Starch

• 2 Tbsp Water
• 2 Tbsp Light Corn Syrup
• 1/3 cup Granulated Sugar
• 1 Egg White room temperature
• 1/2 Tbsp Gelatin Powder
• 1 Tbsp Cold Water
• 1/4 tsp Vanilla Extract

• 12 oz Semisweet Chocolate chopped
• 1 Tbsp Vegetable Oil

Instructions

1. In a large mixing bowl, beat the butter, sugars, and salt together with an electric mixer on medium speed until well combined. Add the egg, egg yolk, and vanilla; beat until incorporated.
2. In a medium bowl, whisk the flour and cornstarch together. Add it to the butter mixture and beat until fully incorporated. Gather the dough into a ball, cover with plastic wrap and refrigerate for at least 2 hours.
3. Preheat the oven to 350°F. Scoop 1 tablespoon sized pieces of dough and roll them into balls. Place the balls of dough 2 inches apart on a baking sheet lined with parchment paper or silicon mat. Bake for 10 to 12 minutes or until the edges of the cookies are lightly browned.
4. Cool on the pan for 5 minutes, then transfer to a wire rack to cool completely.

1. Combine the water, corn syrup, and sugar in a small saucepan fitted with a candy thermometer. Bring to a boil and cook to "soft-ball" stage, about 235°F.
2. Meanwhile, in a large bowl, beat the egg white on medium speed until soft peaks form.
3. Sprinkle the gelatin over the water and set aside to soften. Once the syrup reaches 235°F, add in the softened gelatin and mix until fully dissolved. With the mixer running on low, slowly pour the syrup into the beaten egg white. Add the vanilla. Turn the mixer to medium-high speed and continue to beat until stiff. (This may take around 3-5 minutes)
4. Transfer the marshmallow to a pastry bag fitted with a round tip. Pipe a large kiss of marshmallow on the bottom side of half the cookies. Top with a second cookie to form a sandwich. Refrigerate for 30 minutes.

1. Add chocolate and oil to a heatproof bowl and set it over a pot of barely simmering water. Stir constantly until chocolate is melted and smooth.
2. Working with one cookie at a time, use a fork to dip it into the bowl of melted chocolate. Flip it over to fully coat the cookie in chocolate. Tap off any excess and let it drip back into the bowl. Place the cookies on a wire rack set over a large baking sheet.
3. Refrigerate until chocolate is set. Keep cookies stored in the refrigerator until ready to serve. Cookies with keep for up to 3 days stored in an airtight container.