Preheat oven to 350F convection, or 375F without convection.
Preheat olive oil in a large cast iron pan or a saute pan. Add onions, garlic, carrots, celery and bell pepper. Saute the vegetables over high heat for about 5 minutes, until nicely caramelized and golden brown.
Add the ground pork and continue sauteing for another 4-5 minutes, frequently stirring and breaking up meat clumps into small pieces.
Add the tomato paste and saute for another 1-2 minutes, stirring constantly.
Turn the heat to medium low, add the beef bouillon cube and the beer. Simmer for about 20 minutes, stirring every 5 minutes or so, or until most of the liquid has evaporated.
Remove the filling from heat and let it cool for a few minutes. Add the chopped greens, shredded cheese, egg, salt and pepper. Stir well and set aside.
Generously brush a 9x15-inch baking pan with olive oil. Layer half of the phyllo sheets on the bottom of the pan, drizzling olive oil all over each sheet, including the sides. Add the filling and spread evenly. Fold the sides of the phyllo sheets over the filling and drizzle with olive oil.
Layer the remaining sheets of phyllo dough in the same manner, drizzling each sheet with olive oil. Roll the sides of the phyllo inward. Generously drizzle some olive oil all over the top of the pie and gently spread it with a brush.
Score the pie in to 12 pieces. Do not cut too deep and all the way to the sides.
Bake on top rack for 45 minutes, or until deep golden brown and crispy.
Remove from the oven and allow the pie to cool for 10 minutes before cutting and serving.