Grandpa’s Best Carrot Cake Has an Unexpected Secret Ingredient

There's so much to get excited about when it comes to spring baking: luscious lemon bars, fresh rhubarb pies, and lavender shortbread cookies, to name a few. But, without a doubt, the top spot on our spring baking list goes to carrot cake.

Carrot cake is the humble icon of the season. With its earthy flavors and warming spices, it’s about the most comforting cake there is. To really be the best spring dessert in show, one thing is essential: it has to be moist. Luckily, we’ve discovered a trick to achieve this baking feat every time, and it starts and ends with one simple ingredient.

The Secret Ingredient for a Moist Carrot Cake 

If you want to achieve a perfectly moist and tender carrot cake every time, turn to buttermilk.

This tip comes from our top-rated Sam's Famous Carrot Cake, which, 2,800 five-star reviews would agree, is the best carrot cake recipe on our site.

Sam (recipe submitter Brian D'Amico’s grandfather) was known for delivering homemade carrot cake to his friends and neighbors whenever they wanted one, and every time it was “moist and divine”—thanks to the addition of buttermilk in his famous recipe.

“Everyone who knew him knows of this carrot cake,” said Brian D'Amico. “We'll miss him, but his carrot cake legacy will always live on!”

So, how does buttermilk help one leave a carrot cake legacy?

Why Buttermilk Makes a Difference in Carrot Cake

Buttermilk might seem like an unlikely candidate for a carrot cake, but it provides the cake with unmatched tenderness and depth of flavor. Traditional carrot cake recipes rely solely on oil for moisture, but with this recipe, the addition of buttermilk makes the cake lighter, more tender, and more flavorful. Here’s how it works.

Buttermilk’s acidity reacts with the baking soda in the recipe, creating tiny bubbles of carbon dioxide throughout the batter. This chemical reaction not only helps the cake rise to fluffy perfection but also ensures a moist and tender crumb in every slice.

It’s not just the texture of the cake that's affected. The acidic ingredient introduces a subtle tang to the cake which balances the sweetness of the carrots, pineapple, and raisins, while also complementing the warmth of the cinnamon.

This simple trick guarantees a dessert that's light and airy, yet rich and satisfying—everything you “could possibly ask for” from the quintessential spring dessert. So, if you want to make a carrot cake that lives up to its fullest flavor potential, take a page from Grandpa Sam’s recipe book and always bake it with buttermilk.

How to Make Our Top-Rated Carrot Cake with Buttermilk

This recipe was originally baked in an 8x12-inch pan, but many users prefer baking the batter in two round cake pans to make a stacked layer cake instead.

Start by sifting together the dry ingredients in one bowl (flour, baking soda, cinnamon, and salt) and in a separate bowl, stirring together the wet (sugar, eggs, oil, vanilla, and, of course, buttermilk).

We understand that unless you’re whipping up weekly batches of pancakes, you might not keep buttermilk on hand at all times. So, if you want to save yourself a trip to the store, you can easily make a homemade buttermilk substitute out of milk and vinegar.

Gradually stir the flour mixture into the wet ingredients, then add in the mix of shredded carrots, pineapple, coconut, walnuts, and raisins. Pour it into your greased and floured pan(s), and bake in a 350-degree F oven for one hour (or 45 minutes, if you separate the batter into two cakes).

Once it’s cooled, cover it with a rich cream cheese frosting, and enjoy the “best carrot cake in existence,” according to our users.