In a medium saucepan, pour the whole milk and toss in the split vanilla bean pod along with the scraped seeds. Place the saucepan over medium heat and let it simmer, which should take around 8 minutes.

This process allows the vanilla essence to fully infuse into the milk, creating that delightful base flavor. After simmering, remove from heat and let it sit for about 15 minutes, letting the flavors deepen. Finally, take out the vanilla bean pod and discard it; it has done its job!

Grab a heat-proof mixing bowl and add the egg yolks and granulated sugar. You want to whisk vigorously until the mixture turns smooth and a lighter color. This aeration will help create a fluffy texture in your final cream. Next, sift the cornstarch into the mixture, making sure you whisk again to eliminate any lumps.

While continuing to whisk your egg and sugar mixture, slowly pour in about half a cup of the hot milk. This step tempers the eggs, preventing them from scrambling. Once incorporated, gradually whisk in the remaining milk until all is combined. For a smooth texture, pour the mixture through a fine mesh strainer back into the saucepan.

Now comes the fun part! Cook the combined mixture over medium heat while gently whisking continuously. You’ll notice it thickening and starting to bubble, usually within 5 to 8 minutes. Once it reaches that sweet spot (like a custard consistency), remove it from heat and immediately whisk in the cold butter until fully melted. This will add an extra layer of creaminess to your Pâtissière.

Transfer the luscious pastry cream to a bowl. Press a piece of plastic wrap directly onto the surface. This step is key to preventing a skin from forming on top. Allow the cream to chill in the refrigerator for at least 2 hours or until you’re ready to use it. You can prepare this up to 24 hours in advance; just whisk it again to bring back that smooth texture before serving.