A Dr Pepper milkshake is vanilla ice cream blended with Dr Pepper, and the trick to a thick one is to boil a 16-ounce bottle of Dr Pepper down to a 1/4-cup syrup first, cool it, then blend it with 3 cups of vanilla ice cream for about 30 seconds. That makes two shakes of about a cup each.
This is written up from MyRecipes' Dr. Pepper Milkshake (linked through the Internet Archive, since MyRecipes has since retired the page), with my adaptations listed in the card. I have not taken it through my own kitchen yet. Plain soda waters a shake down fast, which is why the reduction is worth the wait.
Is a Dr Pepper shake the same as a Dr Pepper float?
No. A Dr Pepper float is soda poured over scoops of ice cream in the glass, so you get a fizzy foam head and separate layers. A shake is blended, so the ice cream and Dr Pepper become one thick, smooth drink with little fizz left. And Dr Pepper ice cream is different again: a frozen dessert you scoop, not something you drink through a straw. If you want a frozen drink without dairy, my Dr Pepper slush is blended with ice instead.
Why reduce the Dr Pepper first?
Concentration. A can of soda is mostly water, and the more of it you pour in, the thinner and icier the shake gets while the flavor stays faint. Simmering 16 ounces of Dr Pepper down to a quarter cup keeps the sugar and flavor and loses most of the water, so the shake can stay thick. Cooking does change the taste, though, and one MyRecipes reviewer found the result tasted mostly of vanilla. That is why I added an optional splash of cold Dr Pepper at the end, to bring back some fresh soda flavor at the cost of a little thickness.
What is in the Whataburger Dr Pepper shake?
Whataburger does not publish a recipe. When it introduced the Dr Pepper Shake in April 2019, Whataburger said it was "made with pure Dr Pepper syrup," only available in parts of Texas, Arkansas and Oklahoma, and only for a limited time. Availability has changed since, so check the Whataburger app for your location. The MyRecipes shake on this page was inspired by that release, but it is a homemade version, not a copy of theirs; it gets a concentrated Dr Pepper flavor by boiling the soda down.
More Dr Pepper treats
For the grown-up version, there is a boozy Dr Pepper float. Other soda-fountain ideas are in Dr Pepper drinks, and everything else is in the Dr Pepper recipes.
Frequently asked questions
How much Dr Pepper goes in a milkshake?
For two shakes, one 16-ounce bottle boiled down to a quarter cup, plus up to half a cup cold if you want more soda flavor. The quicker no-cook ratio is about 1 part Dr Pepper to 2 parts ice cream.
How do I keep the shake thick?
Use ice cream straight from the freezer, let the syrup cool completely before it goes in, and stop the blender as soon as it looks frothy. Blending longer warms and thins it.
Can I add milk?
You can, but this recipe does not need any. Add milk a splash at a time only if your blender struggles.
Can I make it with Diet Dr Pepper?
Not the reduction. With no sugar in it, diet soda will not boil down to a syrup, so use it cold in the no-cook ratio instead. I have not tested it, so expect a lighter flavor.
