One look at these Sticky Toffee Pudding Prune Squares and you’ll be longing for the rich and flavorful cake, marshmallow-like meringue, and sweet toffee drizzle. There is a secret to that perfectly moist crumb: the highest-quality dried fruit from California Prunes. The legendary petit d’Agen plum, brought to California from France during the Gold Rush, is dried at its prime, concentrating the natural sugars and creating a flavor-packed treat. These dried fruits make the ultimate baking ingredient, adding superior depth of flavor and moisture. Make sure to have California Prunes in your pantry for whenever you catch that sweet toffee-fueled craving!
The California Prune industry was born in the 19th century and has grown into a symbol of excellence. First, imagine plum trees, filled with jewels of deep purple fruits, basking in the warm, steady sun of California’s lush valleys. Then picture that each tree is hand-tended with the utmost care, ensuring the highest standards of quality. The perfectly ripened fruit is harvested and dried in climate-controlled tunnels, a process that balances temperature, humidity, and time to create the finest product. It is this combination of environment, care, and the art of processing that brings you the California Prune—a choice baking ingredient.
Learn more about California Prunes online at californiaprunes.org and pick them up in your local grocery store in various forms including whole prunes, pitted prunes, diced prunes, and prune juice.
- 9 ounces (255 grams) roughly chopped California Prunes (about 1¼ cups lightly packed)
- ¾ cup (180 grams) boiling water
- ¾ cup plus 1 tablespoon (184 grams) unsalted butter, softened
- 1 cup (220 grams) firmly packed light brown sugar
- 3 large eggs (150 grams), room temperature
- 2 large egg yolks (37 grams), room temperature
- 1 tablespoon (21 grams) molasses (not blackstrap)
- ¾ teaspoon (3 grams) vanilla extract
- 2 cups (250 grams) unbleached cake flour
- 2 teaspoons (10 grams) baking powder
- 1 teaspoon (5 grams) baking soda
- 1 teaspoon (2.25 grams) kosher salt, divided
- 1¼ cups (250 grams) granulated sugar
- 6 large egg whites (180 grams), room temperature
- ¼ teaspoon cream of tartar
- Salted Toffee Sauce (recipe follows)
- Preheat oven to 350°F (180°C). Spray a 13x9-inch baking pan with cooking spray. Line pan with parchment paper, letting excess extend over sides of pan.
- In a medium heatproof bowl, place prunes in an even layer; add ¾ cup (180 grams) boiling water (prunes should be just submerged), and let stand for 15 minutes.
- In the work bowl of a food processor, pulse prune mixture until mostly smooth. (It’s OK if some flecks of prune remain.)
- In the bowl of a stand mixer fitted with the paddle attachment, beat butter and brown sugar at medium speed until fluffy, 3 to 4 minutes, stopping to scrape sides of bowl. Add eggs and egg yolks, one at a time, beating until combined after each addition. Beat in molasses and vanilla. (Mixture may look slightly curdled at this point, but batter will come together.)
- In a medium bowl, whisk together flour, baking powder, baking soda, and ¾ teaspoon (2.25 grams) salt. With mixer on low speed, gradually add flour mixture to butter mixture in two additions alternately with prune mixture, beginning and ending with flour mixture, beating just until combined after each addition and stopping to scrape sides of bowl. (Do not overmix.) Spoon batter into prepared pan; using a small offset spatula, smooth into an even layer. Firmly tap pan on a kitchen towel-lined counter several times to release any air bubbles; using a wooden pick, pop and fill any that rise to surface.
- Bake until a wooden pick inserted in center comes out clean, 26 to 30 minutes. Let cool in pan for 10 minutes. Using excess parchment as handles, remove from pan, and let cool completely on a wire rack.
- In the heatproof bowl of a stand mixer, whisk together granulated sugar, egg whites, cream of tartar, and remaining ¼ teaspoon salt by hand. Place bowl over a saucepan of simmering water. Cook, stirring frequently, until an instant-read thermometer registers 160°F (71°C), 12 to 18 minutes.
- Return bowl to stand mixer. Using the whisk attachment, beat at medium-high speed until bowl is cool to the touch and glossy stiff peaks form, about 8 minutes. Spoon and spread meringue mixture onto cooled cake. Using a handheld kitchen torch, carefully toast meringue, if desired. Cut into bars. Serve with Salted Toffee Sauce.
- ½ cup (100 grams) granulated sugar
- ½ cup (120 grams) heavy whipping cream
- ¼ cup (57 grams) unsalted butter, softened
- 2 tablespoons (42 grams) dark corn syrup
- 2 teaspoons (14 grams) molasses (not blackstrap)
- ¾ teaspoon (2.25 grams) kosher salt
- 2 teaspoons (8 grams) vanilla extract
- In a medium saucepan, stir together sugar, cream, butter, corn syrup, molasses, and salt. Bring to a boil over medium-high heat; reduce heat to medium-low, and simmer, stirring frequently, for 3 minutes. Remove from heat; stir in vanilla. Transfer mixture to a small heatproof bowl. Let cool for 10 minutes before using.
