Ingredients
Equipment
Method
- In a medium heavy-bottomed saucepan, heat the whole milk over medium heat until just steaming with small bubbles forming around the edges. Meanwhile, whisk together the egg yolks, sugar, cornstarch, and salt in a medium bowl until pale yellow and smooth. Slowly pour half the hot milk into the egg mixture in a thin stream while whisking constantly to temper the eggs. Pour the tempered mixture back into the saucepan with the remaining milk.
- Cook the mixture over medium heat, whisking constantly, until it thickens and begins to bubble. Continue whisking and cook for one full minute after the first bubble appears. Remove from heat and whisk in the butter and vanilla extract. Strain through a fine mesh strainer into a clean bowl. Press plastic wrap directly onto the surface of the cream and refrigerate for at least 2 hours until completely cold and set.
- Preheat your oven to 350°F (175°C). Generously grease a standard 12-cup muffin tin with cooking spray or softened butter, coating the sides and bottom of each cup thoroughly.
- In a medium bowl, whisk together the flour, baking powder, and salt. In a stand mixer fitted with the paddle attachment, beat the softened butter and sugar on medium speed for 2 to 3 minutes until light and fluffy. Add the egg, egg yolk, vanilla extract, and sour cream, mixing until fully incorporated and scraping down the bowl as needed. Reduce to low and add the flour mixture in two additions, mixing just until the dough comes together. Do not overmix.
- Using a cookie scoop or heaping tablespoon, portion the dough into each muffin cup, filling about two-thirds of the way. Using your fingers or the back of a small spoon, press the dough evenly across the bottom and up the sides of each cup to form a shallow well. Keep the walls an even quarter-inch thick throughout.
- Bake for 11 to 13 minutes until edges are just barely golden and centers look set but slightly soft. Immediately after removing from the oven, use the back of a small teaspoon to gently press the centers back down while still warm and pliable. Let cool in the tin for 10 minutes, then carefully remove to a wire rack and cool completely before filling.
- Remove the chilled pastry cream from the refrigerator and whisk briefly to restore its smooth, creamy consistency. Transfer to a piping bag fitted with a round tip or a zip-lock bag with one corner snipped. Pipe or spoon the pastry cream into each completely cooled cookie cup, filling to just below the rim. Smooth the top with the back of a small spoon. Refrigerate filled cups while making the ganache.
- Place the finely chopped dark chocolate in a heat-proof bowl. Heat the heavy cream in a small saucepan over medium heat until just simmering. Pour the hot cream over the chocolate and let sit undisturbed for 2 full minutes. Add the butter and corn syrup if using, then stir gently from the center outward until completely smooth and glossy. Allow the ganache to cool for 5 to 7 minutes until slightly thickened but still pourable.
- Remove the filled cookie cups from the refrigerator. Spoon a generous teaspoon of ganache over each pastry cream filling, allowing it to spread naturally to the edges. Refrigerate for at least 20 minutes to allow the ganache to set completely. Garnish with a tiny pinch of flaky sea salt if desired just before serving.
Notes
Pro Tips: Always make the pastry cream first — it needs at least 2 hours to chill before assembly. Temper the eggs slowly by adding hot milk in a thin, steady stream while whisking constantly to avoid scrambling. Press plastic wrap directly onto the pastry cream surface while it chills to prevent a skin from forming. Press cookie cup centers immediately after baking while still warm and pliable — don't wait. Use a good-quality dark chocolate bar (not chips) for the smoothest, glossiest ganache. Let the ganache cool to the right temperature before pouring — it should fall in a thick, slow ribbon off a spoon. Never fill warm cookie cups — cool completely first or the pastry cream will melt.