Step by step

1. Preheat oven to 180°C. Butter and flour three 20 cm cake pans.

2. Make the cake layers: In a medium bowl, combine sour cream with lemon juice, lemon zest, finely-chopped rosemary, vanilla, and almond extracts. Set aside.

3. In a Stand Mixer Bowl, combine cake flour, sugar, baking powder, and 3/4 tsp salt. Attach to Stand Mixer with Flat Beater. Turn to speed 1 to combine dry ingredients. Continuing on speed 1, add 170 g butter 1 tbsp at a time until mixture is sandy and crumbly in appearance. Stop Mixer and scrape down sides.

4. Add eggs, one at a time, allowing each egg to mix in before adding the next. Stop Stand Mixer and scrape down sides. Turn Stand Mixer to speed 4 and add ⅓ of the sour cream mixture. Mix for 2 minutes, then stop and scrape. Turn to speed 4 and add next ⅓ of sour cream mixture. Mix for 2 minutes. Stop and scrape then turn back to speed 4 for final addition of sour cream mixture. Let mix for 2 minutes.

5. Evenly divide mixture between three cake pans and bake for 22-27 minutes or until sides of cake are slightly pulling away from edges. Let cakes cool in their pans for 10 minutes, then flip out onto wire racks to cool completely before frosting and assembling cake.

6. Make the berry jam: Combine 90 g blueberries and 75 g blackberries in a small Food Processor or Chopper. Process until pureed. Stop and add in chia seeds, process for another 30 seconds. Jam will thicken as it sits. Reserve additional berries for garnish.

7. Make the frosting: In clean bowl attached to Stand Mixer with Flat Beater, cream 230 g butter on medium speed for 2 minutes. Stop Stand Mixer and add in powdered sugar, vanilla bean paste, and salt. Turn Stand Mixer on to low speed to combine, stopping to scrape if needed, then increase speed to high to whip frosting for 2-3 minutes Turn Stand Mixer to low speed and add in 2 Tbsp of milk or cream. Whip on high speed. Add additional milk or cream if needed to get fluffy and spreadable consistency.

8. To assemble cake, place bottom layer on cake platter. Line edges around cake with parchment paper. Add about 100 g frosting to center of cake layer and spread or pipe evenly to edges, making a small ridge around perimeter to hold in fruit jam. Add 3-4 tbsp of fruit jam and spread, leaving an inch border around the edge of the cake layer. Top with another layer of cake and repeat frosting and jam. Top with remaining layer of cake and top with frosting. Lightly spread frosting onto sides of cake, letting cake layers show through for naked cake effect. Remove parchment lining around bottom layer. Top cake with a beautiful mound of fresh berries and ring rosemary sprigs around edges.