Step 1: Prepare the Oven and Cupcake Pan

Start by preheating your oven to 350°F or 175°C. Line a standard muffin tin with cupcake liners. This ensures even baking and makes removing the cupcakes easy once baked. Preparing this in advance keeps the batter from sitting too long, which can affect texture.

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Step 2: Cream Butter and Sugar

In a large mixing bowl, combine the softened butter and granulated sugar. Using a hand mixer or stand mixer, beat the mixture until it becomes light, pale, and fluffy. This step is important because it incorporates air into the batter, which helps create soft cupcakes.

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Step 3: Add Eggs and Vanilla

Add the eggs one at a time, mixing well after each addition. This ensures a smooth and stable batter. Stir in the vanilla paste or extract, which enhances the flavor and gives the cupcakes a warm, aromatic base.

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Step 4: Combine Dry Ingredients

In a separate bowl, whisk together the flour, baking powder, and salt. Mixing these ingredients separately ensures even distribution, which prevents uneven rising during baking.

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Step 5: Mix Wet and Dry Ingredients

Gradually add the dry ingredients into the butter mixture, alternating with the milk. Begin and end with the dry ingredients. Mix until just combined. Avoid overmixing, as this can make the cupcakes dense instead of light and tender.

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Step 6: Fill and Bake

Divide the batter evenly among the cupcake liners, filling each about two thirds full. Place the tray in the preheated oven and bake for about 18 to 20 minutes, or until a toothpick inserted into the center comes out clean.

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Step 7: Cool the Cupcakes

Remove the cupcakes from the oven and let them cool in the pan for a few minutes before transferring them to a wire rack. Allow them to cool completely before filling, as warm cupcakes can melt the filling.

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Step 8: Prepare the Custard Filling

In a saucepan, whisk together the milk, flour, sugar, egg yolk, salt, and vanilla. Place the pan over medium heat and cook while whisking continuously. The mixture will gradually thicken into a smooth custard.

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Step 9: Cook Until Thick and Smooth

Continue cooking until the custard becomes thick enough to coat the back of a spoon. This step requires patience and constant stirring to avoid lumps or burning. Once thickened, remove from heat.

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Step 10: Cool the Custard

Transfer the custard to a bowl and cover it with plastic wrap directly touching the surface. This prevents a skin from forming. Let it cool completely before using.

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Step 11: Core the Cupcakes

Once the cupcakes are fully cooled, use a small knife or cupcake corer to remove the center of each cupcake. Be careful not to cut too deep, leaving enough base to hold the filling.

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Step 12: Fill with Custard

Spoon or pipe the cooled custard into the hollowed centers of each cupcake. Fill generously, ensuring each bite has a creamy center.

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Step 13: Prepare the Ganache

In a small saucepan, heat the heavy cream until it just begins to simmer. Pour the hot cream over the chocolate chips in a bowl. Let it sit for a minute, then stir until smooth. Add the butter and salt, stirring until glossy.

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Step 14: Top with Ganache

Spoon the ganache over each cupcake, allowing it to gently spread over the top. The ganache should be smooth and slightly thick, creating a classic finish.

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Step 15: Let the Ganache Set

Allow the cupcakes to sit at room temperature until the ganache firms up slightly. This step ensures a perfect texture and presentation