Blackberry Lemon Cake with Mascarpone Frosting
If there’s one thing worth celebrating right now, it’s that I’m headed into April with a month of consistent running under my belt. A month of diving back into the treadmill lifestyle, feeling more comfortable + confident each week, and it’s what I am beyond grateful for in this moment. It’s been a hell of journey since the blood clot debacle of 2024. A series of ups + downs, and too many moments of feeling like I’m getting my groove back to shortly there after be side-lined by a new ache + pain. And it’s been a pretty heartbreaking road to recovery, and the past few month have felt especially challenging. Late February was my time to dip my toe back into the running waters, and do so with a lot of caution. March was time to dust of the cobwebs. Fast forward to the day before April, I have 4 weeks of consistent running under my belt, and my biggest hope is that this is the fresh start that I’ve been looking for.
So 5 miles in today and my first outdoor run in months coming up in just a few days calls for a celebratory cake. Going all in on this Blackberry Lemon Cake with Mascarpone Frosting was my priority this weekend. My first cake of 2026. Obviously I went for something super fruity - lemon + berry anything being one of my favorite cake combos that simply never gets old. The shake-up was this mascarpone frosting. Half cream cheese + half mascarpone for a frosting that was velvety, smooth, and rich. All the creamy cheeses keeps this from turning into a frosting that feels to buttery (one of my least favorite things ever). It leans heavy into the tangy cheese flavor + it’s the perfect pairing for a bright lemon cake. Light, fruity, and so good we’re cutting ourselves extra big slices here at the house.
For the blackberry filling
4 c. fresh blackberries, 3 c. blackberries cut in half + 1 cup whole berries
1/4 c. sugar
1 tbsp fresh lemon juice
1 tbsp corn starch
2 tbsp water
For the cake
8 oz. mascarpone, cold
1/2 c. butter, room temperature
1/2 c. vegetable oil
2 c. sugar
6 egg whites
juice of 1 lemon
2 tsp vanilla
1/4 tsp almond extract
2 tbsp lemon zest
3 c. flour
2 tsp baking powder
1/2 tsp baking soda
1 tsp salt
3/4 c. almond milk
For the frosting
1/2 c. butter, room temperature
8 ounces cream cheese, room temperature
8 ounces mascarpone, cold
5 c. powdered sugar
1/2 tsp almond extract
Start with the filling - Add all of the ingredients to a saucepan over medium heat. Bring the mixture to simmer, stir, and continue to cook at a low simmer for about 10 minutes. Reduce the heat to low + continue to cook for 20 minutes. Turn off the heat + transfer the berries to a glass mason jar. Leave on the counter for 1 hour, then secure the lid + transfer to the fridge to cool completely.
Now make the cake - Prep 3 6-inch baking tins for baking. Rub oil around the surface of each cake pan then lightly dust with flour - dumping any extra flour. Line the bottom of each pan with parchment. To make the cake batter, start by adding the mascarpone, butter, oil, sugar and lemon zest to a stand mixer. Mix at medium speed for 2 minutes - the mixture should be light + fluffy. Add in the egg whites, vanilla, almond + extract- mixing on low until its just blended together. Next add in the baking powder, baking soda, salt, and half of the flour, mixing on low until it’s just mixed in. Add in half of the milk + all of the lemon juice, mixing on low until it looks well mixed. Add in the rest of the flour + then the rest of the milk, gradually increasing the speed over the next 3 minutes to medium/medium high speed. Batter should be light, creamy and perfectly smooth.
Transfer the batter into the 3 prepared baking tins, and bake for about 30 minutes - rotating the pans in the oven at the 25 minute mark. The cake should be golden brown on the top + pass the toothpick test. Let the cakes cool at room temperature in the hot baking pans for 30 minutes. Then remove the cakes from their tins + leave out to cool completely. Trim each of the layer - removing the domed top. Wrap each cake layer individually in plastic wrap + place in the freezer for at least 2 hours (or overnight).
When you’re ready to assemble your cake, make your frosting. Add the butter, cream cheese, marscarpone, and half of the powdered sugar to the mixer. Mix on low until the powdered sugar is fully mixed in, then mixing on medium speed for 1 minutes. Reduce the speed back to low + add in the remaining powdered sugar and almond extra. Mix on low until the powdered sugar has been fully absorbed + increase the speed back to medium, and then medium high, whipping the frostting together at the highest speed for 1 minutes. The frosting should be airy, smooth, and spreadale. Finally, add in 3 tbsp of the prepared blackberry filling, folding in the blackberries by hand or mixing on low.
To assemble the cake, follow these steps:
Place a small dollop of frosting on a cake tray + top with one of the cake layers.
Spread a thin layer of the frosting across the cake + pipe a thick layer of frosting around the edge of the cake. Spread half of the blackberry filling over the frosting, use a small spatula to spread the filling to the edge of the cake - reaching the piped border.
Place the 2nd cake layer on top, and repeat step two
Place the 3rd cake layer on top of the cake.
Proceed to dirty ice the entire cake + place it in the fridge for 30 minutes.
Take the cake + continue to ice and decorate with the remaining blackberry frosting.
Cut into, serve at room temperature, and enjoy!
