Instructions

Preparing the Ingredients & Pans (30 minutes)

1. Measure out all the ingredients.  It’s always best to use a kitchen scale to measure solid ingredients.  If you must use cups to measure the flour and sugar, spoon them into the cups and sweep off the excess with a flat knife.  Do not pack the ingredients into the measuring cup.
2. Make sure that all the ingredients are at room temperature.  This is important!  Let the buttermilk sit out for 30 minutes or until room temperature.  Warm up the eggs by soaking them in hot tap water for 10 minutes.  Soften the butter by cutting it in cubes and microwaving it in 5-second intervals, smashing the butter with a spoon between each interval.
3. Get the pans ready.  Lightly butter three 6-inch cake pans that are 2 inches deep.  Line the bases of the pans with parchment paper.
4. Prepare the cake strips.  Cinch a cake strip around each cake pan, then remove them from the pans and soak them in cold water for at least 10 minutes.
5. Preheat the oven to 350 F.  The oven should be preheated before you start baking the cake, or you might forget about it.

Making the Cake (20 minutes + 20 minutes baking + 35 minutes cooling)

1. Sift dry ingredients.  Sift the flour, baking powder, baking soda, and salt into a medium bowl.  Set aside.
2. Cream the butter and sugar.  Cream the softened butter and caster sugar with a handheld electric mixer until smooth and noticeably lightened in color, about 3 minutes.
3. Add the eggs and vanilla.  Beat in the eggs one at a time, scraping down the sides and bottom of the bowl as needed.  Add the vanilla extract and beat until smooth and fluffy, about 1 minute.
4. Finish the batter.  Fold in the lemon zest and poppy seeds with a flexible spatula, then gently mix in the sifted flour mixture.  Carefully stir in the buttermilk and lemon juice and mix until well blended.
5. Install the cake strips.  Remove the cake strips from the cold water and gently squeeze them to remove the excess water.  (The strips should be really wet, but not dripping.  Don’t wring them out.) Cinch the strips around each prepared pan.
6. Divide the batter.  Equally divide the batter among the three pans, using the spatula to smooth the surface of the batter.
7. Bake.  Bake the cakes at 350 F for 20 minutes, until a toothpick inserted in the center comes out clean.  Let the cakes cool in the pans for 5 minutes, then flip the cakes onto wire racks and peel off the parchment paper.  Let the cakes cool completely on the racks, about 30 minutes.

Making the Lemon Cream Cheese Buttercream (10 minutes)

1. Cream.  Beat the butter and cream cheese until smooth and fluffy, about 1-2 minutes.  Scrape down the sides and base of the bowl with a flexible spatula.
2. Finish the icing.  Sift the icing sugar into the bowl and add the lemon juice and vanilla extract.  (Omit the vanilla for a stronger lemon flavor.)  Beat on low speed for 30 seconds, then turn the mixer up to medium-high speed and beat until smooth and fluffy.  Scrape down the bowl as needed.
3. Make any adjustments.  If the icing is too thick, add additional lemon juice.  If the icing is too thin, add more sifted icing sugar.  The icing should be soft and spreadable, but still hold its shape when piped.

Decorating the Cake (40 minutes + 50 minutes chilling)

1. Layer the cakes.  Place one of the cooled cake layers bottom side up on a cake base and put the base on a cake turntable.  Spread a liberal amount of icing on top of the cake, then repeat with the other two layers, ending with a layer of icing on top.
2. Crumb coat the sides.  Spread icing on the sides of the cake with an angled spatula, filling in gaps with additional icing.  Scrape off most of the icing from the sides and top of the cake with the angled spatula or a bench scraper.  Chill the crumb coated cake for 30 minutes.
3. Ice the cake.  Spread a layer of icing over the sides and top of the chilled cake, smoothing it with the angled spatula and/or the bench scraper.  Fill in any air pockets or gaps with additional icing and smooth it again.  Chill the cake for 20 minutes.
4. Smooth the finish.  Do any small touch ups to the icing and finish smoothing the icing with the angled spatula.
5. Decorate.  Place the remaining buttercream in a piping bag fitted with an open star tip, such as the Wilton 1M or the Ateco 824.  Pipe rosettes of buttercream around the top of the cake and sprinkle with poppy seeds if desired.  Place a small lemon wedge on each rosette.
6. Serve.  Chill the cake until ready to serve, then cut in slices with a smooth-bladed knife.  Store leftover cake in an airtight cake carrier to keep it moist and refrigerate.