Honey Syrup (make 2 days in advance, at same time as Baklava):
Place sugar, honey, lemon juice, and water into a small pot. Bring to a boil and simmer 3-4 mins. Remove from heat and cool completely.
Reserve 1/4 cup of syrup to use on cake layers if desired.
Baklava (make 2 days in advance):
Preheat oven to 325F and grease the sides and bottom of a 6" pan with removable bottom.
Pulse walnuts in a food processor a few times until medium to finely chopped. Transfer to a small bowl and combine with the cinnamon.
Roll filo dough out onto a clean surface. Using a 6" cake pan or cake ring as a guide, cut out a circle shape through all the layers. Cover filo completely with a damp towel and keep it covered while you work.
Place one circle of filo dough in the bottom of your pan, brush with meted butter. Repeat until you've done 10 layers of dough. Brush top layer with butter and spread 1/4 cup of walnut mixture over top.
Continue layering filo dough with brushing each layer with butter in between for a total of 5 layers this time. Brush top layer with butter and spread 1/4 cup of walnut mixture over top.
Repeat two more times with 5 layers of filo each and finally with another 10 layers. The breakdown is like this:10 layers buttered filo1/4 cup walnut mixture5 layers buttered filo 1/4 cup walnut mixture 5 layers buttered filo1/4 cup walnut mixture5 layers buttered filo1/4 cup walnut mixture10 layers buttered filo (I did not butter the very top, but you can)
Cut the baklava into into about 1 1/2" wide strips, then cut across to form squares. Try not to cut all the way through the very bottom layer.
Bake for 1h 15mins or until top layer is golden brown. Remove from over and immediately spoon syrup over the baklava. Let sit uncovered until completely cool, then cover with a tea towel. Leave at room temperature for 2 days.
Honey Walnut Cake:
Note: If making your own walnut flour, pulse the walnuts a few times, measure out 1/4 cup, then pulse again mixed with the flour. Otherwise it will turn to walnut butter.
Preheat oven to 325F. Grease and flour two 6" cake rounds and line with parchment.
In a medium bowl, whisk flour, walnut flour, baking powder,and salt until well combined. Set aside.
Using a stand mixer fitted with a paddle attachment, cream butter and sugar on med-high until pale and fluffy (approx 3mins). Reduce speed and add eggs one at a time fully incorporating after each addition. Add honey and vanilla and blend well.
Alternate adding flour mixture and milk mixture, beginning and ending with flour (3 additions of flour and 2 of milk). Fully incorporating after each addition.
Bake for about 40-45 mins 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. Allow cakes to cool completely.
Honey Cinnamon Swiss Meringue Buttercream:
Place egg whites and sugar into the bowl of a stand mixer, whisk until combined.*
Place bowl over a pot with about 1" of simmering water. Whisk constantly until the mixture is hot and no longer grainy to the touch (about 3mins). Or registers 160F on a candy thermometer.
Place bowl on your stand mixer and whisk on med-high until the meringue is stiff and cooled (the bowl is no longer warm to the touch (approx. 5-10mins)).
Switch to paddle attachment. Slowly add cubed butter and mix until smooth.** Add honey and cinnamon and mix until incorporated.
(optional) Trim tops of each cake layer just slightly or poke holes into them with a bamboo skewer. Drizzle each layer with about 2 Tbsp of the reserved honey syrup.
Frost each layer of cake with approximately 2/3 cup of buttercream, spread evenly.
Place one layer of cake on a cake stand or serving plate. Gently remove baklava from the pan and place on top of the frosted cake layer. Place remaining layer of cake on top of the baklava, frosting side down. Press gently.
Frost and smooth the outside with a thin crumb coat. Chill for 20mins.
Spread about 2/3 cup of frosting on the top of the cake. Smooth the top then use a small offset spatula to do a swirl.
Using a piping bag fitted with a medium petal tip (I used #125), pipe rows of buttercream on the sides of the cake. Starting from the top and working your way down, narrow side of the tip pointing up. I started a bit higher than intended, but it gave the top a nice lip that I could fill with chopped walnuts.
Sprinkle chopped walnuts and baked filo chips along the top of the cake if desired.
* Wipe your mixer bowl and whisk down with lemon juice or vinegar to make sure it is completely grease free and make sure there is no trace of yolk in your whites or your meringue will not stiffen. ** The buttercream may look like it's curdled at some point. Keep mixing until it is completely smooth. If it looks soupy, place it in the fridge for 20mins and rewhip.Baklava recipe adapted from Natasha's Kitchen.