Split the vanilla bean lengthwise and scrape out the seeds. Add both the seeds and the pod to the milk and cream.
Cover with plastic wrap and gently heat without boiling. Let it infuse for 30 minutes.
Once the milk has infused, soak the gelatin in plenty of very cold water for 15 minutes, ensuring it is fully submerged.
Meanwhile, whisk the egg yolks with the sugar until pale and creamy.
Bring the infused milk to a boil, then slowly pour it through a fine-mesh sieve over the whisked egg yolks, stirring constantly.
Remove the vanilla pods, pressing them firmly to extract any remaining seeds.
Mix everything, then pour the mixture back into the saucepan.
Heat over medium heat, stirring constantly with a rubber spatula, scraping all corners well to prevent the cream from sticking to the bottom.
Stir in figure-eight motions (or back and forth) without interruption until the cream coats the spatula. You'll recognize the correct consistency when your finger leaves a trace when drawn across the spatula. If you use a thermometer, the temperature should not exceed 82 to 84°C (180 to 183°F).
Lift the saucepan off the heat twice during cooking, then return it to the heat, continuing to stir. This allows the cream to thicken gently without exceeding the recommended temperature. It will thus be silky and lump-free. By lifting the saucepan, you avoid quickly reaching 84°C (183°F).
⚠️ Warning: the cream must never boil. Above 84°C (183°F), the eggs will coagulate and the cream will be ruined.
Off the heat, add the squeezed gelatin and mix well. Strain the mixture through a fine-mesh sieve.
Let it cool, stirring regularly to prevent a skin from forming on the surface.
To speed up the cooling process, place the bowl in an ice bath. Do not let the cream set.
Whip the very cold heavy cream in the stand mixer, gradually increasing the speed. It will whip more easily this way.
Make sure to whip it to a soft consistency so you can easily incorporate it into the custard.
Once the custard is almost cool but still liquid, add three-quarters of it to the softly whipped cream.
Note: normally, whipped cream is folded into the custard, but I prefer to do it this way as it creates a smoother and more homogeneous mixture.
Gently fold the mixture from the bottom up using a spatula.
Then add the remaining custard in three portions, folding gently each time.
Use the Bavarian cream immediately before it sets.