Equipment
Ingredients
Cupcake Batter
- 125 g all-purpose flour
- 100 g granulated sugar
- 100 g dark brown sugar, packed
- 40 g cocoa powder, unsweetened
- 4 g baking soda
- 2 g baking powder
- 3 g salt
- 120 ml vegetable oil
- 120 ml buttermilk, room temperature
- 1 egg, large, room temperature
- 5 ml vanilla extract
- 120 ml hot water, freshly boiled
Peanut Butter Frosting
- 115 g unsalted butter, softened to room temperature
- 250 g creamy peanut butter, conventional, not natural or separated
- 180 g powdered sugar, sifted if clumpy
- 30 ml heavy cream, cold
- 5 ml vanilla extract
- 3 g flaky sea salt
Nutrition (per serving)
Nutrition is estimated per serving. Nutrients without complete source data are omitted.
Full nutrition
- Calories
- 470 kcal
- Protein
- 7 g
- Carbohydrates
- 47 g
- Fat
- 30 g
- Fiber
- 3 g
- Sugar
- 34 g
- Sodium
- 418 mg
- Saturated Fat
- 9 g
- Trans Fat
- 0 g
- Monounsaturated Fat
- 8 g
- Polyunsaturated Fat
- 3 g
- Cholesterol
- 39 mg
- Potassium
- 216 mg
- Calcium
- 51 mg
- Iron
- 1.1 mg
- Magnesium
- 57 mg
- Phosphorus
- 130 mg
- Zinc
- 0.9 mg
- Vitamin A
- 84 mcg
- Vitamin C
- 0 mg
- Vitamin D
- 0.1 mcg
- Vitamin E
- 2.2 mg
- Vitamin K
- 1 mcg
- Vitamin B6
- 0.1 mg
- Vitamin B12
- 0.1 mcg
- Thiamin
- 0.05 mg
- Riboflavin
- 0.10 mg
- Niacin
- 3.0 mg
- Folate
- 25 mcg
- Water
- 27 g
- Alcohol
- 0 g
- Caffeine
- 8 mg
Sources: Aggregated Public Data, USDA FoodData Central
Method
Preheat your oven to 175°C (350°F). Line a 12-cup muffin tin with paper liners.
In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, dark brown sugar, cocoa powder, baking soda, baking powder, and salt until completely uniform and free of lumps.
In a separate medium bowl, mix the vegetable oil, buttermilk, egg, and vanilla extract until thoroughly combined.
Pour the wet ingredients into the dry ingredients and stir gently until just combined. Do not overmix.
Carefully stir the freshly boiled hot water into the batter. The mixture will become very thin, which is exactly right for a light crumb.
Divide the batter evenly among the 12 cupcake liners, filling each about two-thirds full. Bake at 175°C (350°F) for 18 to 20 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cupcakes to cool in the tin for 5 minutes, then transfer them to a wire cooling rack to cool completely before frosting.
To make the frosting, use an electric mixer to beat the softened butter and creamy peanut butter in a mixing bowl on medium speed until perfectly smooth and well blended, about 2 minutes.
Add the powdered sugar, heavy cream, vanilla extract, and flaky sea salt to the peanut butter mixture. Beat on low speed until incorporated, then increase the speed to medium-high and whip for 3 minutes until light and fluffy.
Generously pipe or spread the peanut butter frosting onto each fully cooled cupcake. Garnish with an extra pinch of flaky sea salt just before serving.
Chef's Notes
- Using hot water at the end of the batter mixing process blooms the cocoa powder, releasing complex flavor compounds that dramatically intensify the chocolate taste.
- Vegetable oil is 100 percent fat, whereas butter contains water. Oil coats flour proteins better, inhibiting gluten formation and ensuring these cupcakes stay incredibly tender and moist for several days at room temperature.
- Always use conventional peanut butter like Jif or Skippy for the frosting. Natural peanut butters that separate in the jar will cause the delicate frosting emulsion to break and become unpleasantly greasy.
- The batter will seem alarmingly thin after adding the hot water. Trust the process; this high-hydration batter is the exact secret to a featherlight crumb that rises beautifully.
Storage
Refrigerator: 5 days — Bring to room temperature for 30 minutes before serving so the frosting softens.
Freezer: 3 months — Freeze unfrosted cupcakes wrapped tightly in plastic wrap. Frosting can also be frozen separately.
Troubleshooting
Cupcakes sink in the middle
Cause: The oven door was opened too early during baking, causing a sudden drop in temperature, or leavening agents were expired.
Fix: Fill the sunken crater with a generous scoop of frosting. The visual flaw will be completely hidden.
Prevention: Keep the oven door completely closed until at least the 15-minute mark, and check baking soda and powder expiration dates.
Frosting is greasy, split, or won't hold shape
Cause: A natural or separated peanut butter was used, or the butter was far too warm and began to melt.
Fix: Place the frosting bowl in the refrigerator for 15 to 20 minutes to firm up the fats, then whip it again on high speed to re-emulsify.
Prevention: Always use conventional, stabilized peanut butter for this frosting, and ensure butter is pliable but still cool to the touch.
Cultural Context
The pairing of chocolate and peanut butter is a quintessential American flavor combination that skyrocketed in popularity during the early 20th century, largely popularized by commercial candy cups. The magic relies on the contrast between the bitter, deep notes of cocoa and the rich, roasted, savory-sweet profile of peanut butter. Serving this combination in a cupcake format transforms a nostalgic childhood candy flavor into an elevated dessert perfectly suited for birthdays, parties, and picnics.
