01 -
Preheat oven to 175°C. Line two baking sheets with parchment paper.
02 -
In a stand mixer using the paddle attachment, beat unsalted butter and granulated sugar on medium-high, scraping the bowl occasionally, until light and fluffy, about 2 to 3 minutes. Add the egg, corn syrup, and vanilla; blend until incorporated.
03 -
In a separate bowl, whisk together all-purpose flour, cocoa powder, cornstarch, baking soda, and salt.
04 -
Gradually add dry ingredients to the wet mixture with mixer on low speed. Mix until just combined into a soft, slightly sticky dough.
05 -
Using a 22 mL (1 ½-tablespoon) spring-loaded scoop, drop dough balls onto prepared baking sheets. Bake for 8 to 9 minutes, until cookies are slightly puffed and edges are set.
06 -
Remove baking sheets to cooling racks. After several minutes, transfer cookies off trays to cool completely. Cookies will flatten as they cool.
07 -
In a microwave-safe bowl, heat milk chocolate chips and vegetable oil in 15-second intervals, stirring after each, until smooth. Drizzle or pipe chocolate over each cookie. Refrigerate for at least 30 minutes until set.
08 -
In a cleaned stand mixer bowl with paddle attachment, beat unsalted butter on medium until smooth. Add sifted cocoa powder and powdered sugar; beat until very light and fluffy, about 3 minutes, scraping bowl as needed. Add warm water and vanilla extract; continue beating on medium-high for 2 minutes until aerated.
09 -
Pipe or spread filling onto the underside of half of the cookies. Gently press a remaining cookie on top to form sandwiches.
10 -
Serve immediately or store assembled Fudge Rounds in an airtight container at room temperature for 1 day, refrigerated for up to 5 days, or frozen for up to 1 month. Serve chilled for a fudgier texture.