Preheat oven to 350°.

Grease and flour two 9-inch round cake pans or put a 9-inch parchment circle on the bottom of each pan and then spray pans.

In large bowl, combine flour, baking powder, baking soda, and salt. Sift into another large bowl.

In another large bowl, beat butter and sugar at medium speed 2 minutes, until fluffy. Beat in egg yolks, one at a time, mixing well after each. Beat in lemon juice, zest, and vanilla.

At low speed, beat in flour mixture alternately with buttermilk, beginning and ending with flour mixture (about 3 flour additions and 2 buttermilk additions). Beat just until blended.

In small glass or metal bowl with clean beaters, beat egg whites with cream of tartar until stiff peaks form.

With rubber spatula, gently fold egg white mixture, in thirds, into batter.

Spread batter in prepared pans.

Bake 35 to 40 minutes, until cake tester inserted in centers comes out clean.

Cool in pans on racks 5-10 minutes Invert onto racks. Let sit until completely cool.

With a mixer, whip cream to stiff peaks (do not under whip!), and set aside.

In another bowl, mix cream cheese, sugar, vanilla, and salt. Whip until fluffy.

Gently fold in whipped cream into cream cheese mixture in three additions, making sure to be short and gentle in order to not deflate whipped cream.

Store in fridge. Frost cake just before serving.

In a small saucepan, combine sugar and lemon juice. Bring to a boil and cook just until sugar is dissolved.

Using a large knife or cake leveler, level cake tops, if necessary.

Using a pastry brush, brush lemon syrup onto each cake.

Take one cake layer and spread a layer of frosting on top.

Stack the second cake layer.

Spread a layer of frosting over the whole cake (This is called a "crumb coat." This layer of frosting is just enough to cover the cake so that none of the color is showing through. It does not have to be even as it will be covered up with the roses.)

Cut the tip of the icing bag, insert a star tip (I use Wilton 1M), and fill the bag with icing.

Look at your cake and decide how many rows of roses you want going up he sides. Place your icing tip in the center of where you want your bottom row and gently squeeze the bag, starting in the center, and wrap around your center 2 times. Repeat this until you have gone all the way around your cake.

Start the next row up using the same method and continue until the sides are frosted.

Once you have finished the sides of your cake, cover the top using the same method. Start from the outside and work your way in.

Garnish with fresh lemons.