Best Butterscotch Pudding

From America’s Test Kitchen Season 14: Decadent Desserts
Why this recipe works:
For butterscotch pudding with rich, bittersweet flavor, we made butterscotch sauce by cooking butter, brown and white sugar, corn syrup, lemon juice, and salt together into a dark caramel. We made the process more foolproof by first boiling the caramel to jump-start it and then reducing the… read more

Serves 8
When taking the temperature of the caramel in step 1, tilt the pan and move the thermometer back and forth to equalize hot and cool spots. Work quickly when pouring the caramel mixture over the egg mixture in step 4 to ensure proper thickening. Serve the pudding with lightly sweetened whipped cream.
Ingredients

• tablespoons unsalted butter, cut into 1/2-inch pieces
• cup (3 1/2 ounces) granulated sugar
• cup packed (3 1/2 ounces) dark brown sugar
• cup water
• tablespoons light corn syrup
• teaspoon lemon juice
• teaspoon salt
• cup heavy cream
• cups whole milk
• large egg yolks
• cup cornstarch
• teaspoons vanilla extract
• teaspoon dark rum

Instructions

1. Bring butter, granulated sugar, brown sugar, water, corn syrup, lemon juice, and salt to boil in large saucepan over medium heat, stirring occasionally to dissolve sugar and melt butter. Once mixture is at full rolling boil, cook, stirring occasionally, for 5 minutes (caramel will register about 240 degrees). Immediately reduce heat to medium-low and gently simmer (caramel should maintain steady stream of lazy bubbles—if not, adjust heat accordingly), stirring frequently, until mixture is color of dark peanut butter, 12 to 16 minutes longer (caramel will register about 300 degrees and should have slight burnt smell).
2. Remove pan from heat; carefully pour 1/4 cup cream into caramel mixture and swirl to incorporate (mixture will bubble and steam); let bubbling subside. Whisk vigorously and scrape corners of pan until mixture is completely smooth, at least 30 seconds. Return pan to medium heat and gradually whisk in remaining 3/4 cup cream until smooth. Whisk in 2 cups milk until mixture is smooth, making sure to scrape corners and edges of pan to remove any remaining bits of caramel.
3. Meanwhile, microwave remaining ¼ cup milk until simmering, 30 to 45 seconds. Whisk egg yolks and cornstarch together in large bowl until smooth. Gradually whisk in hot milk until smooth; set aside (do not refrigerate).
4. Return saucepan to medium-high heat and bring mixture to full rolling boil, whisking frequently. Once mixture is boiling rapidly and beginning to climb toward top of pan, immediately pour into bowl with yolk mixture in 1 motion (do not add gradually). Whisk thoroughly for 10 to 15 seconds (mixture will thicken after a few seconds). Whisk in vanilla and rum. Spray piece of parchment paper with vegetable oil spray and press on surface of pudding. Refrigerate until cold and set, at least 3 hours. Whisk pudding until smooth before serving.
Technique
Smoother Route to Pudding?
Pudding recipes almost always have you temper the yolks and cornstarch (i.e., add some hot dairy to the mixture to gradually raise its temperature), add everything to the remaining dairy in the pot, and stir constantly as the mixture slowly comes to a boil and thickens. Inevitably, bits of egg still overcook and need to be strained. We wondered if there was a better way.
EXPERIMENT:
We made one batch of pudding the conventional way and a second batch in which the yolks never saw the heat of the stove: We added a little warm milk to the yolks and cornstarch, brought the remaining “dairy” (in our recipe, the butterscotch mixture) to a boil, and then dumped this hot liquid over the egg mixture and whisked briefly as the pudding thickened almost instantly.
RESULTS:
The conventional pudding needed straining, while the “no-cook” custard was utterly smooth and perfectly thickened.
EXPLANATION:
Boiling pudding is overkill. When cornstarch is combined with liquid, it thickens between 144 and 180 degrees, while yolks diluted by liquid coagulate between 180 and 185 degrees—significantly lower temperatures than the boiling point of 212 degrees. Whisking the hot butterscotch mixture into the yolk mixture heated the pudding to about 185 degrees—plenty hot to properly thicken it but not so hot that the yolks overcooked.
DUMP AND STIR
Technique
A New Way to Consistently Perfect Caramel
The rich flavor of our butterscotch pudding depends on cooking the caramel mixture to 300 degrees before adding the cream, but it’s easy to over- or undercook that mixture when it’s boiled from start to finish (the usual approach). Our more forgiving method: Boil the caramel over medium heat until it reaches 240 degrees, then reduce the heat to medium-low, and gently simmer it until it reaches 300 degrees. The simmer phase takes about 12 to 16 minutes—plenty of time in which to grab a thermometer and the cream.

—