Place the strawberries in a blender. Blend until the strawberries becomes a puree.
Pour the pureed strawberries in a medium saucepan, place over medium heat.
Bring to a simmer, and stir often.
Cook the puree until it reduces to ¾ cup. You will use ½ cup for the cake, and ¼ cup for the buttercream frosting.
Once you have ¾ cups, pour in a bowl and cover with plastic wrap directly on the surface of the puree so it doesn’t form a crust. Let the puree cool down.
Pre-heat the oven to 350ºF.
Grease and line the bottom of 3 8-inch cake pans with a circle of parchment paper. Grease the parchment and the sides of the pan as well.
In a small bowl, mix together the flour, baking powder, baking soda, and salt. Whisk to combine. Set aside.
Use an electric mixer to beat the butter at medium speed for 30 seconds.
Add the granulated sugar, the oil, and beat together with the butter for another 1 to 2 minutes, until the mixture is light and fluffy.
Add the eggs, one at a time, mixing until incorporated before adding the next egg.
Add the vanilla and mix to combine.
Pour the sour cream, and ½ cup of the strawberry puree in the bowl and mix.
Add half of the buttermilk to the bowl and mix on low.
Add half of the dry ingredient mixture and stir to combine.
Add the remaining buttermilk and mix.
Finish by adding the last half of the dry ingredients. Stir to combine.
Divide the batter evenly between the 3 pans.
Bake the Strawberry cake layers in the pre-heated oven for about 35 minutes, until a toothpick comes off clean when inserted in the cake.
Remove the cakes from the oven and let them cool down in the pan for 10 minutes. Then flip the cakes onto a wire rack until they have cooled completely.
Add the chopped strawberries, sugar, and lemon juice to a saucepan.
Cook the strawberries, stirring occasionally, at medium-high heat.
When the strawberries come to a boil, turn the heat down and continue to cook at medium-low heat.
Cook until a thermometer reads between 200 and 220ºF. The jam will be dark, and thick.
Remove the jam to a bowl, place a piece of plastic wrap directly on the surface of the jam, and let it cool down. Refrigerate for a couple of hours before using.
Beat the butter in the bowl of a mixer for 30 seconds. Add the cream cheese and beat for another 30 seconds on medium-speed.
Add half of the powdered sugar, mix on low until combined. Raise the speed and beat on medium speed for just a few seconds.
Add the strawberry puree and mix on low.
Add the remaining powdered sugar, mix on low, and then raise the speed to medium-high, and beat for one minute.
To assemble the cake, place a cake layer on a cake plate.
Spread a thin layer of the Strawberry Cream Cheese Frosting on top of the cake.
Pipe a ring of frosting around the edges of the cake.
Spread a layer of jam inside the ring of frosting.
Top with another cake layer.
Repeat the process by spreading a layer of frosting on the cake, then piping a ring of frosting around the edges, and filling the center with jam.
Top with the final cake layer.
Spread a thin amount of frosting on top of the cake and on the sides.
Place the cake in the fridge until this layer of frosting has chilled, about 20 to 30 minutes.
Remove the cake from the fridge and spread the remaining frosting on top of the cake and on the sides.
Place the halved strawberries all over the cake.
