To prepare the cake:
- Preheat the oven to 350 degrees and spray a half sheet pan (18″ x 13″ x 1″) with baking spray. Line the bottom with a rectangle of parchment paper and set aside.
- In a large bowl or the bowl of a stand mixer, cream together the Kerrygold unsalted butter and sugar on medium speed until fluffy, about 2 minutes.
- Scrape the sides of the bowl and add the egg whites and vanilla and mix to combine.
- Scrape the sides of the bowl and add half of the milk plus the lemon juice and zest. Mix until combined and then add about half of the flour as well as the baking soda, baking powder, and salt.
- Scrape the sides of the bowl and add the remaining milk followed by the remaining flour. Mix on low only until combined and scrape the sides of the bowl.
- Fold in any unincorporated bits and spread the batter into the prepared pan.
- Bake in the oven for about 13 minutes or until a toothpick inserted comes out clean. Set aside to cool completely.
To prepare the cream:
- Combine the whipping cream and lavender in a bowl and cover with plastic wrap.
- Allow to rest in the fridge overnight or at least 6 hours.
- When ready to prepare the cream, cream the cream cheese and sugar on medium speed in a large bowl until combined, about 30 seconds.
- Slowly drizzle in the cream while the mixer is on low to incorporate.
- Add the vanilla extract and continue beating on medium speed until the mixture has thickened and stiff peaks form.
- Add a smidge of light purple or lavender food coloring if desired. Set in the fridge until ready to use.
To assemble the cake:
- Invert the cake out of the pan and cut along the long edge into three equal pieces. You’ll wind up with 3 rectangles of cake about 5-1/2” x 12-1//2” in size.
- Spread 1/3 of the preserves on each piece of cake in a thin even layer.
- Place on piece of the jammy cake on a serving dish and spread 1/3 of the lavender whipped cream on top. Smooth to flatten the whipped cream without overworking the cream and then top with another jammy piece of cake. Repeat this process once more finishing with the remaining layer of cake and lavender whipped cream on top.
- Place in the freezer to firm up the top quickly, about an hour, and then cover gently with plastic wrap and continue freezing for another 6 hours. You can clean up the edges of the cake by cutting through the frozen layers to even them up, if desired.
- Otherwise, slice ½” wedges for serving and top with fresh raspberries, if desired.