Vanilla Bean Cream Cheese Frosting

1. Make the Custard

Start by combining 12 ounces of milk and a split vanilla bean in a 3-quart stainless steel saucier. Bring this mixture to a gentle simmer over medium heat. As soon as it begins to bubble, turn off the heat, cover the pot, and let the vanilla bean steep for about 30 minutes. This steeping process is crucial as it allows the vanilla to infuse deeply into the milk, providing a rich, aromatic base for your frosting.

2. Prepare the Egg Mixture

While the vanilla is steeping, whisk together 8 ounces of sugar and 1.5 ounces of cornstarch in a medium bowl. Add in the 3 large eggs and continue whisking until the mixture is smooth and well combined.

3. Temper the Eggs

After the vanilla has finished steeping, bring the milk back to a simmer and discard the vanilla bean. Gradually ladle some of the hot milk into the egg mixture, whisking constantly to prevent the eggs from scrambling. This process is known as tempering and helps to gently heat the eggs without cooking them too quickly.

4. Cook the Custard

Pour the tempered egg mixture back into the pot with the remaining milk. Cook this over medium heat, whisking constantly. You'll notice the mixture will start to thicken and become lumpy within about 3 minutes. Keep whisking until it reaches a thick, pudding-like consistency. This continuous whisking is essential to prevent lumps and ensure a smooth custard.

5. Finish the Custard

Once the custard is thick and bubbling, stir in 1/2 ounce of vanilla extract. Pour the finished custard into a large baking dish, cover it with plastic wrap, and refrigerate it for about an hour until it is completely cool.

6. Make the Buttercream

In a stand mixer fitted with the paddle attachment, beat 16 ounces of softened cream cheese and 12 ounces of softened unsalted butter until the mixture is light and fluffy. This should take about 5 minutes. Once the custard is cool, stir it to loosen it up. Switch the stand mixer to the whisk attachment, then gradually add the custard and 1 ounce of freshly squeezed lemon juice to the cream cheese and butter mixture. Whip everything together until it is smooth and fully combined.