Step 1: Prepare the Mixture

1. Combine Dry Ingredients: In a medium saucepan, whisk together the cornstarch, granulated sugar, and salt.
2. Add Milk: Gradually add the whole milk to the dry ingredients, whisking until smooth and combined.

Step 2: Cook the Pudding

1. Heat Mixture: Place the saucepan over medium heat and cook, stirring constantly, until the mixture begins to thicken and comes to a gentle boil (about 5–7 minutes).
2. Whisk Egg Yolks: In a separate bowl, lightly beat the egg yolks.
3. Temper the Egg Yolks: Once the milk mixture is thickened, slowly ladle a small amount of the hot mixture into the beaten egg yolks, whisking continuously to prevent curdling. Repeat this process a couple of times.
4. Combine Mixtures: Pour the tempered egg yolk mixture back into the saucepan with the remaining pudding mixture, whisking to combine.

Step 3: Add Flavorings

1. Add Maple Syrup: Stir in the pure maple syrup and continue to cook for another 2–3 minutes, stirring until the pudding is thick and creamy.
2. Finish with Vanilla and Butter: Remove from heat and stir in the vanilla extract and unsalted butter (if using) until fully incorporated.

Step 4: Serve

1. Cool: Pour the pudding into individual serving dishes or a large bowl. Let it cool to room temperature, then refrigerate for at least 2 hours until set.
2. Enjoy: Serve chilled or at room temperature, optionally garnished with whipped cream or additional maple syrup.