Vanilla Pudding:

1. In a medium saucepan, combine the whole milk, granulated sugar, cornstarch, and salt. Whisk the mixture until the cornstarch and sugar are fully dissolved.

2. Place the saucepan over medium heat and cook, stirring constantly, until the mixture thickens and starts to boil. This should take about 5-7 minutes.

3. In a separate bowl, lightly beat the egg yolks. Gradually add a small amount of the hot milk mixture to the egg yolks while whisking continuously. This will temper the eggs and prevent them from curdling.

4. Pour the tempered egg yolk mixture back into the saucepan with the rest of the milk mixture. Cook over medium heat, stirring constantly, until the pudding thickens and reaches a pudding-like consistency. This should take about 2-3 more minutes.

5. Remove the saucepan from the heat and stir in the unsalted butter and pure vanilla extract until fully incorporated.

6. Transfer the vanilla pudding to a bowl or individual serving dishes. Cover the surface of the pudding with plastic wrap to prevent a skin from forming. Refrigerate for at least 2 hours to chill and set.

Sugared Rhubarb in Orange Juice:

1. In a medium bowl, combine the thinly sliced rhubarb and granulated sugar. Toss the rhubarb until evenly coated with sugar. Let it sit for about 15 minutes to macerate.

2. In a separate bowl, combine the freshly squeezed orange juice and orange zest.

3. After the rhubarb has macerated, pour the orange juice mixture over the sugared rhubarb and stir gently to combine. Let the rhubarb soak in the orange juice for another 10-15 minutes.

Assembly:

1. To serve, spoon the chilled vanilla pudding over crispy cookies into individual bowls or glasses.

2. Top each serving of vanilla pudding with a generous amount of the sugared rhubarb in orange juice.

3. Optionally, garnish with additional orange zest or a sprig of mint for added freshness and presentation.