Step 1

Preheat the oven to 350 F and place a rack in the middle of the oven.

Step 2

In a medium bowl add in the sugar and lemon zest. Rub the zest into the sugar with your fingers until fragrant and the sugar begins to clump.

Step 3

Pour in the flour, baking soda, baking powder, and salt and whisk to combine.

Step 4

Add in the butter, yogurt, eggs, and vanilla.

Step 5

Use the paddle attachment to mix the ingredients first on medium low until just combined, then turn it to high speed for 30 seconds.

Step 6

Scrape the sides and bottom of the bowl.

Step 7

In a separate bowl, stir together the blackberries and 15 grams of flour. Pour the flour coated berries into the cake batter and use a spatula to fold them in.

Step 8

Spray the cake pan with your baking spray and then pour in the cake batter.

Step 9

Smooth out the cake with a rubber spatula.

Step 10

Bake the cake in the preheated oven for 30 minutes. After 30 minutes, rotate the cake 180 degrees and bake for another 20-25 minutes.

Step 11

When the cake is finished baking, check it by sticking a toothpick into the center of the cake. If the toothpick comes out clean, the cake is fully baked.

Step 12

Remove the cake from the oven and leave it to cool for 10 minutes before removing the spring form.

Step 13

After 10 minutes, remove the springform.

Step 14

Allow the cake to cool completely before assembling.

Step 15

Add the blackberries (fresh or frozen) into a medium bowl, along with the sugar and lemon juice.

Step 16

Stir to combine and leave at room temperature to macerate until ready to use. If you are making them the day before, place them in the fridge overnight.

Step 17

In a large metal bowl or the top portion of a double boiler, add in the egg yolks, sugar, salt, lemon zest and lemon juice. Whisk to combine.

Step 18

Add about 2" of water into a sauce pan or the bottom of the double boiler. Bring to a simmer and then reduce the heat to low so that it maintains a simmer.

Step 19

Place the bowl with the egg and lemon mixture over the pot of simmering water. Whisk constantly, cooking the mixture until it thickens. It's done when the mixture is thick like mayo, essentially when you stop whisking the mixture should stop moving, it will sort of just firm up.

Step 20

Once thick, immediately remove the bowl from the pot of water and turn off the heat.

Step 21

Add the cold mascarpone into the hot curd, one spoonful at a time. Whisk one spoonful of mascarpone into the lemon curd until completely dissolved before adding in the next spoonful.

Step 22

Continue adding the mascarpone in until it is all used up. Pour the mixture into a large shallow bowl and place a piece of plastic onto the surface. Place the bowl in the fridge until cold and thick.

Step 23

Once the lemon curd mixture is cold and set, spoon about 75 grams into a small bowl and set aside.

Step 24

In a large bowl, whip the cold heavy cream on medium high speed until almost stiff peaks form. Be careful not to over whip the mixture.

Step 25

Add half of the whipped cream into the lemon curd and fold to combine. Then, add in the other half of the whipped cream and fold until combined.

Step 26

* Optionally, level off the domed top of the cake first with a serrated knife.

Step 27

Slice the cake into 2 layers with a serrated knife.

Step 28

Place the bottom layer of the cake onto a dish or cake stand, ideally lined with parchment for easy transportation.

Step 29

Scoop half of the lemon curd whip onto the bottom layer of cake and use the back of a spoon or rubber spatula to spread it out.

Step 30

If frozen blackberries were used they will be soft enough as is but if you used fresh blackberries, mash half of them in a separate bowl with a fork - these will be used for the middle filling.

Step 31

Scoop half of the macerated blackberries out of the bowl, leaving as much of the liquid in the bowl as possible. Sprinkle the blackberries over the whipped cream so they are evenly dispersed.

Step 32

Layer the top layer of cake over the frosting and press down gently.

Step 33

Scoop the remaining whipped cream onto the top of the cake. Using the back of a spoon to make loose swoops on top. Spoon the extra lemon curd mixture around the top of the cake and use the spoon to swirl them in.

Step 34

Spoon the remaining macerated blackberries, again trying not to scoop up too much of the liquid, onto the whipped cream and lemon curd.

Step 35

If time leave the cake to firm up slightly for an hour or two in the fridge before slicing but it can be sliced and served immediately.