Baklava is a rich, decadent dessert recipe made of layers of flaky filo dough, filled with chopped roasted walnuts, and sweetened with a sticky honey sauce.
Make syrup: Combine 1 1/2 cups water, 1 1/2 cups granulated sugar, 3/4 cup honey and 2 teaspoons vanilla extract in a medium sized saucepan. Bring to a boil, stir to dissolve sugar, and then reduce heat as low as possible so that it can still maintain a gentle simmer. Maintain simmer and cook uncovered for about 25-30 minutes. Transfer to a glass measuring cup and allow to fully cool.
Preheat oven to 325° F.
Toast nuts: Spread 1 pound walnuts onto baking sheet into single layer. Toast in preheated oven for 15-20 minutes, stirring occasionally to prevent burning. Remove from oven and allow to fully cool. Use a large knife to chop them into small pieces or pulse in food processor (my preferred method). Combine with 1 teaspoon cinnamon and set aside.
To assemble and bake baklava:
Prepare dough: Unroll 16 ounces phyllo dough. Cut sheets so that they fit perfectly in a 9x13-inch baking dish. Dampen and ring out two clean kitchen towels or large sheets of paper towels and place them above and below the phyllo dough. Keep the dough covered at all times with moist cloths so that it doesn't dry out.
Create base: Using a pastry brush, paint the bottom of the baking dish with 1/2 cup salted butter. Add two sheets of dough, spread a thin layer of butter on top, then repeat with two more sheets of dough, butter, dough, butter, etc. until you have a base layer of 8 sheets.
Add nuts and layer: Now, you will lay down a thin layer of melted butter, 2-3 tablespoons of the crushed toasted cinnamon nuts, and top with two sheets of dough. Repeat this butter/nut/dough layering process until you are left with 8 remaining sheets of dough.
Finish layering: The top layer will consist of two sheets of dough, butter, two sheets of dough, butter, and so on. If you run out of butter, you may need to melt more, but the goal is to have a very thin layer every time you add it and I like to paint the top with the last bit of butter.
Cut servings: Cut the baklava prior to baking with a very sharp knife. Cut through the top layer but do not go all the way through to the bottom. You want the bottom layer to remain intact. I prefer triangles so I cut rectangles first and then cut across on a diagonal.
Bake: Cook baklava in preheated 325°F oven for about 50 minutes until the top is crisp and golden.
Add syrup: As soon as you remove baked baklava from the oven, pour the cooled syrup over the entire top, allowing it to sink down through all the layers. This is why you didn't cut all the way through. By leaving that bottom layer whole, it won't make your baklava soggy. Allow everything to cool.
Serve and enjoy: Best if served same day, but can be stored for several days at room temperature. I prefer to cover loosely with a kitchen towel to prevent anything from touching it because airflow is needed to prevent the baklava from getting soggy.