Lemon Blueberry Bombshell Cake

This is the lemoniest (and possibly sweetest) cake ever. There's lemon in everything. EVERY. THING. And it's glorious. I feel like Will Farrell- MORE COW BELL! MORE LEMOOOON! Okay, sorry, I don't know what happened there. Anyway, I'm gonna just say when you go to make this cake, just buy a bag of lemons and plan on using most of them. This is the perfect spring or summer cake. I'd recommend making the lemon curd the night before- this just makes it easier when you go to make the cake because it requires some cooling.
Side note, this was a cake for our two year birthday of our book club because we are adorable! I will post a pic of our group at the bottom so that you can look if you want and can just stop reading by then if you don't ;)

This recipe makes three 8-inch round cakes OR 24 cupcakes (with a little extra).

For the Lemon Simple Syrup
1/2 c granulated sugar
1/4 c water
Zest and juice of one lemon

1. Combine all ingredients in a small sauce pan and bring to a boil.
2. Reduce to a simmer for about 10 minutes, or until the mixture thickens to a syrup.
3. Remove from heat and cool.
**You will have extra syrup left over from the cake. KEEP IT! Put it in your cocktails! Pairs great with cucumber gin. Just saying.

For the Lemon Curd
I am still using Ina Garten's lemon curd recipe because it's delicious.

3 lemons *bullshit, Ina.

1 ½ c granulated sugar

¼ pound unsalted butter, room temp (that’s 1 stick)

4 extra-large eggs

½ c lemon juice (3 – 4 lemons) *Really, it depends so much on how juicy your lemons are. Sometimes it takes me 6 lemons, and sometimes 4. So what I'm saying is buy more lemons than you think you will need. 

1/8 tsp salt

1. Using a vegetable peeler, remove the zest of 3 lemons, being careful to avoid the white pith. Put the zest in a food processor. Add the sugar and pulse until zest is very finely minced into the sugar.

2. Cream the butter and beat in the sugar and lemon mixture.

3. Add one egg at a time, and then add the lemon juice and salt. Mix until combined.

4. Pour mixture into a 2-quart saucepan and cook over low heat until thickened, about 10 minutes, stirring constantly. The lemon curd will thicken at about 170F, or just below a simmer. For this recipe, I kept cooking it for about 10 more minutes because I wanted it to be thicker so that it would not squish out of the cake layers.
5. Remove from heat and run through a strainer to get any lumps or bigger pieces of zest out of it. Cool or refrigerate. I put it in mason jar and let it cool slightly before putting the lid on and putting it in the fridge. 

For the Lemon Blueberry Cake
1/2 c vegetable oil
1/2 c (One stick) unsalted butter, room temperature
3 large eggs, separated
2 c granulated sugar
2 c all-purpose flour
1 1/2 c cake flour

1 1/2 c buttermilk
1 tsp salt
1 1/2 tsp baking soda
2 tsp baking powder
1 tsp vanilla
1 pint blueberries
Zest and juice of 1 lemon (although more wouldn't really hurt)

1. Preheat oven to 350F and prepare three 8-inch round cake pans with goop.
2. Combine oil, butter, and granulated sugar and cream together in a stand mixer fitted with paddle attachment.

3. In a small bowl, whip up the egg whites to soft peaks. Set aside.
4. Add egg yolks one at a time, into the butter and sugar mixture, incorporating each before adding another.
5. Add vanilla.
6. Combine flour, salt, baking soda, and baking powder together in a separate bowl.
7. Alternate dry ingredients and buttermilk, incorporating each into the batter before adding more. Start and end with the dry ingredients. **SAVE a little of the dry ingredients at the end.
8. Take your last bit of dry ingredients and toss your blueberries around in there. This will help the blueberries to be coated in flour and not sink to the bottom of the cakes.

9. Throw in your egg whites and fold them in to incorporate.
10. Incorporate the blueberries, lemon zest, and juice into the batter and mix by hand. You don't want to use the electric mixer for this part because you don't want to break the blueberries apart.
9. Divide batter into pans and bake for 25 - 30 minutes or until a toothpick inserted comes out clean.

For the Lemon Buttercream 
4 sticks unsalted butter, room temperature
5 1/2 c powdered sugar (sifted)
1/4 tsp salt
1 tsp vanilla
Zest of one lemon

1. Cream butter in a stand mixer with paddle attachment.
2. Slowly (in batches) add powdered sugar until incorporated. *You can add more powdered sugar if you feel it needs it. Sometimes I add more if it's a humid day.
3. Add vanilla, salt, and lemon zest and mix until incorporated.

Assembly
1.  Place a dollop of frosting on your cake board to hold layers in place.
2. If the cake layers are a bit uneven, level off tops with a serrated knife.
3. Put some buttercream in one piping bag and the lemon curd in another piping bag.
3. Place your first layer on the cake board. Take the simple syrup and brush the top of the cake with the syrup.

4. Take the buttercream and first make a circle of buttercream all around the edge of the top of the cake. This will create a dam to make sure that no lemon curd escapes! Continue to make a spiral of with the buttercream all the way into the middle of the cake.

4. Take the lemon curd and fill in the buttercream spiral with the lemon curd. (See video below)

5. Add next layer and then repeat.

6. Once the final layer has been put on, soak that layer with the simple syrup, and then cover the cake in buttercream.
7. If you want to do the cute little lemon drops on top, put some lemon curd in a ziploc bag and cut a TINY hole in the corner of the bag. Make little drops of lemon curd in a spiral on top of the cake. Take a toothpick and run it through each dot of curd to create a dragging pattern. You may need to wipe off your toothpick every once in a while as you go.