Move the oven rack to the bottom middle position and pre-heat to 300 degrees F.
Add the almonds to a food processor and pulse a few times until they resemble a rough gravel. Slice the vanilla beans down the center and scrape out the "beans", adding them to the food processor along with the pistachios and sugar (save the pods for later). Continue pulsing another 12-15 times until the nuts are chopped into small pieces.
To assemble the baklava, brush a generous amount of melted butter onto the bottom and sides of a 9x9 baking pan. Unroll the phyllo dough and cut in half (you should have two 9"x14" stacks of phyllo). Starting at the edge of the pan closest to you, place a sheet of phyllo at the bottom allowing the extra phyllo to drape over the edge furthest from you. Brush the phyllo with melted butter. Fold the extra 5" of phyllo hanging off the side furthest from you onto itself. Brush the top of this surface with butter then lay another piece of phyllo down starting from the edge furthest from you (so the overhang is closest to you), butter then fold the overhang over. Repeat 4 more times.
Sprinkle about half of the nut mixture evenly over the phyllo. Layer another 4 sheets of phyllo using technique above (buttering and alternating sides you overlap). Evenly spread the rest of the nut mixture on the phyllo and cover with 6 sheets of phyllo using the technique above. To finish, cut 2 sheets of phyllo to be exactly 9"x9", butter and layer. Press down gently on the baklava to allow the nuts to settle.
Using a serrated edge steak knife, cut the baklava (all the way through) in a crisscross pattern. Drizzle the remaining butter on top brushing the top to ensure they're evenly coated. Put it in the oven for about 1 1/2 hours or until the top is golden brown.
To make the vanilla milk syrup, put the sweetened condensed milk in a small saucepan along with the vanilla pods and heat over low heat until the mixture is warm and bubbly. Use a spatula to try and scrape any remaining vanilla beans out of the pods and into the milk. Turn off the heat and let the pods steep in the milk until the baklava comes out of the oven.
When the baklava is golden brown on top, remove it from the oven and immediately pour the vanilla milk syrup evenly over the cuts in the baklava (discarding the vanilla pods). Allow the baklava to cool completely in the pan. You can serve it as soon as its cooled, but it tastes best the next day.