Prepare the Pastry Cream:

• In a bowl, whisk together egg yolks, 1/4 cup sugar, salt, and a pinch of nutmeg until smooth. Stir in 2 tablespoons flour.
• In a medium saucepan, heat 1 cup half-and-half over medium-low heat until it begins to simmer (do not boil).
• Slowly whisk the hot half-and-half into the egg mixture to temper, then pour the combined mixture back into the saucepan.
• Continue whisking over medium-low heat until the cream thickens and bubbles gently (about 2–3 minutes). Remove from heat.
• Stir in 2 tablespoons butter and 1 1/2 teaspoons vanilla extract until fully melted.
• For an ultra-smooth texture, pass the pastry cream through a fine-mesh strainer into a bowl.
• Cover the surface with plastic wrap (to prevent a skin) and chill in the refrigerator for 1–2 hours. (If desired, fold in whipped cold heavy cream after chilling for extra lightness.)

Bake the Cupcakes:

• Preheat your oven to 350°F (175°C). Line a 12-cup muffin pan with cupcake liners.
• In a large bowl, sift together flour, baking powder, and salt.
• In another bowl, cream together the softened butter and sugar until light and fluffy (about 3–4 minutes). Mix in the vanilla extract.
• Add the whole eggs one at a time, beating well after each addition.
• In a separate clean bowl, beat the egg whites until stiff peaks form.
• Alternately add the dry ingredients and the half-and-half to the butter mixture, beginning and ending with the dry ingredients. Gently fold in the beaten egg whites until just combined.
• Divide the batter evenly among the cupcake liners, filling each about 2/3 full.
• Bake for 18–25 minutes or until a toothpick inserted into the center comes out clean. Allow cupcakes to cool completely on a wire rack.

Assemble the Cupcakes:

• Once the cupcakes are cool, use a cupcake corer or a small knife to carefully remove a 1-inch deep circle from the center of each cupcake, leaving a “cap.”
• Fill each cavity generously with the chilled pastry cream using a piping bag fitted with a small round tip.
• Replace the cupcake “cap” on top of the filling if desired.

Make the Chocolate Ganache:

• Place the chocolate in a heatproof bowl.
• In a small saucepan, heat the heavy cream and corn syrup until just simmering.
• Pour the hot cream mixture over the chocolate. Let it sit for 5 minutes, then whisk until smooth and glossy.
• Allow the ganache to cool until it reaches a spreadable consistency (about 10–15 minutes).

Top the Cupcakes:

• Spoon or pipe the ganache generously over each filled cupcake.
• Let the ganache set at room temperature. For best texture, refrigerate the cupcakes and serve at room temperature.