Combine Dry Ingredients: In a medium saucepan, mix 1/2 cup of sugar with 1/4 cup of cornstarch. This combination forms the base of your custard, ensuring it has the right sweetness and thickness.

Crack 2 large eggs into a bowl. Gradually whisk these into your sugar and cornstarch mixture. This step is crucial for integrating the eggs smoothly, which is key for a creamy custard. Make sure to whisk vigorously to avoid lumps.

In a separate saucepan, gently heat 2 cups of milk. The milk should be warm but not boiling – this helps in blending the milk into the egg mixture without cooking the eggs prematurely.

Slowly pour the warm milk into your egg mixture, continuously whisking. This gradual process, known as tempering, ensures that your eggs don't curdle and the mixture remains smooth.

Place the saucepan over medium heat. Keep stirring constantly for about 5-7 minutes. As the mixture heats, it will begin to thicken. Once it reaches a pudding-like consistency, remove it from the heat. This is your cue that the custard is ready.

Stir in 1 teaspoon of vanilla extract. This adds a subtle but distinct flavor, elevating the custard. For a twist, you can add a hint of cinnamon or even a touch of chocolate to the custard for different versions of the Bougatsan.

Let the custard cool to room temperature, then cover it and chill in the refrigerator. This chilling process helps the custard set and develop its flavors.

Prepare the Croissants: Take 4 large croissants and carefully slice them in half, ensuring not to cut all the way through. This step is crucial for creating a pocket for the custard.

Once the custard is chilled, remove it from the fridge. Gently spoon or pipe the custard into the croissant. The goal is to evenly fill the croissant with the creamy custard without overstuffing.

Final Touches: Just before serving, dust each Bougatsan with powdered sugar. This not only adds a sweet finish but also gives a beautiful, professional look to your dessert.