Preheat oven to 350F. Grease and flour three 6" cake rounds and line with parchment.

In a medium bowl, whisk flour, poppy seeds, baking powder, and salt until well combined. Set aside.

Using a stand mixer fitted with a paddle attachment, cream butter and lemon zest until smooth. Add sugar and beat on med-high until pale and fluffy (approx 3mins).

Reduce speed and add eggs one at a time fully incorporating after each addition. Add vanilla.

Alternate adding flour mixture with milk & lemon juice, beginning and ending with flour (3 additions of flour and 2 of milk & lemon juice). Fully incorporating after each addition.

Spread batter evenly between the prepared pans and smooth the tops.

Bake for about 30-35mins or until a toothpick inserted into the center comes out mostly clean.

Place cakes on wire rack to cool for 10mins then turn out onto wire rack to cool completely.

Place lemon juice and sugar into a small saucepan, stir to combine. Cook over medium heat, stirring often, until simmering and all sugar has dissolved. Cool completely before using on cake.

Using a stand mixer or hand mixer beat butter until pale and creamy.

Reduce speed to low. Add powdered sugar 1 cup at a time and mix on low until well blended. Increase speed to medium and beat for 3 minutes. Add vanilla and continue to beat on medium for 1 minute.

Slowly add chilled cream cheese one cube at a time (about 1 tablespoon at a time). Beat well until blended and ensure no lumps of cream cheese remain.

If needed, add cornstarch or meringue powder 1 tablespoon at a time to stiffen the frosting (I didn't but this is an option). Add a pinch of salt to cut some sweetness if desired.

Run mixer on low for a couple of minutes to remove any air bubbles.

Trim the crust off the top of each cake layer and brush each with the lemon simple syrup. About 1-2 Tbsp per layer.

Place one layer of cake on a cake stand or serving plate. Top with ⅔ cup of frosting, spread evenly. Repeat with the remaining layers and apply a thin coat of frosting all over the cake. Chill for 20mins.

Use the remaining frosting to frost the cake in a rustic manner.

Decorate with fresh, edible flowers and lemon slices if desired.