Pumpkin Olive Oil Cake With Vanilla Bean German Buttercream

What Is German Buttercream?

You’re in for a treat if you’ve never made German buttercream. Sometimes called mousseline buttercream, this frosting is made by whipping butter into a pastry cream. Unlike American buttercream, it isn’t overly sweet—it’s smooth, creamy, and easy to flavor. I use vanilla bean for this recipe for a rich, fragrant finish that pairs beautifully with pumpkin spice.

Why Olive Oil Makes the Best Cakes

One of the reasons I love olive oil cakes is that they are almost impossible to dry out. Olive oil keeps the crumb moist and tender; in this recipe, the pumpkin puree adds even more softness. The combination makes for a cake that stays delicious for days and tastes even better the next day.

Ingredients You’ll Need for Pumpkin Olive Oil Cake

• Flour – All-purpose flour works perfectly. No need to sift.
• Leavening Agents – Baking soda and baking powder help the cake rise.
• Warm Spices & Flavorings – Pumpkin pie spice, cinnamon, and a splash of vanilla extract bring out that classic fall flavor.
• Sugars – White granulated and brown sugar mix gives just the right sweetness and depth.
• Pumpkin Puree – Be sure to use 100% pumpkin puree, not pumpkin pie filling.
• Olive Oil – The star of the cake keeps the crumb moist and adds a subtle fruity richness.
• Eggs – Help bind the batter and give structure to the cake.

Ingredients You’ll Need for German Buttercream

• Milk – The base for the pastry cream.
• Sugar – Sweetens the pastry cream.
• Eggs – Whisked into the custard for richness.
• Cornstarch – Thickens the pastry cream.
• Salt – Just a pinch to balance the sweetness.
• Vanilla Bean – Scraped into the butter for flavor (or substitute vanilla bean paste).
• Butter – Whipped until light and creamy, blended with the cooled pastry cream.

How to Make Pumpkin Olive Oil Cake with German Buttercream

• Step 1: Prep your pan. Spray a 9×13-inch sheet pan with nonstick spray and line with parchment. Preheat the oven to 350°F.
• Step 2: Mix the dry ingredients. Whisk together flour, baking powder, baking soda, pumpkin pie spice, cinnamon, and salt in a large bowl.
• Step 3: Mix the wet ingredients. In another bowl, whisk olive oil, granulated sugar, brown sugar, eggs, pumpkin puree, and vanilla extract.
• Step 4: Combine the batters. Add the wet mixture to the dry and stir until just combined. Pour into the prepared pan and bake for 35–40 minutes, or until a toothpick inserted in the center comes out clean.
• Step 5: Cool the cake. Remove from the oven and invert onto a parchment-lined cooling rack. Let cool completely.
• Step 6: Make the pastry cream. Whisk together eggs, milk, sugar, cornstarch, and salt in a saucepan until smooth. Cook over medium-high heat, stirring constantly, until thickened.
• Step 7: Cool the pastry cream. Pour into a bowl, press plastic wrap directly on the surface, and let cool to room temperature.
• Step 8: Make the buttercream. In a stand mixer, whip room-temperature butter until light and fluffy. Scrape in the vanilla bean (or add vanilla bean paste), then beat in the cooled pastry cream until smooth.
• Step 9: Assemble the cake. Slice the cooled cake into three equal rectangles. Spread or pipe ⅓ of the frosting onto the first layer, top with the second piece of cake and another ⅓ of the frosting, then finish with the last layer and the remaining buttercream. Leave the sides unfrosted for a rustic look. Chill for at least 1 hour before serving.

Tips for Success

• Cool completely – Both the cake and the pastry cream must be fully cooled before making the buttercream.
• Choose your style – Leave the sides unfrosted for a simple presentation or save extra buttercream to frost the edges.
• Storage – Keep the cake in the refrigerator. It tastes great both chilled and at room temperature.
• Customize the frosting – German buttercream takes on flavors beautifully, so try adding espresso, caramel, or even a splash of bourbon for variation.

Easy Pumpkin Olive Oil Cake Recipe for Fall Baking

This Pumpkin Olive Oil Cake with Vanilla Bean German Buttercream is an easy fall dessert that looks elegant but doesn’t require much fuss. Moist, flavorful, and topped with the silkiest frosting, it’s the kind of cake you’ll want to bake all season long.