Filo (also "phyllo") is an extremely thin pastry dough that is commonly used in Greek cuisine. You can find filo in the frozen section of most grocery stores near the desserts and pastries. Filo is sold rolled in 1 pound boxes of 20-30 sheets, and will keep for months in the freezer. The brand I buy is 14"x18"; you can buy smaller sizes or even cut dough with scissors. Defrost it by leaving it overnight in the refrigerator; avoid defrosting at room temperature as the sheets are more likely to stick to one another. Filo will keep for a few weeks in the refrigerator.
Filo very quickly dries out when exposed to air. When using filo, be sure you have all the ingredients handy and the oven preheated. Have a convenient area to unroll the filo clean and ready and keep a clean damp cloth or a plastic wrap handy to keep the supply of dough covered while you work. Typically, you will be spreading melted margarine on the individual sheets - it is handy to have a pastry brush, and you should focus on quick, broad strokes, working from the edges in; don't saturate the sheets, but quickly get some margarine on each sheet before it dries.
It's fun to cook with filo! Try making filo triangles filled with tofu and vegetables at home, or experiment with other ideas.
In this recipe, I suggest brown rice syrup; the result in baklava tastes like honey! Other sweeteners that can be used include maple syrup (use about 1/2 as much as you would brown rice syrup, and beware that this may change significantly the taste you would expect of baklava), molasses (use 1/2 as much), frozen fruit juice concentrate (experiment, but try using about 3/4 the amount), various brands that mix fruit juice concentrate with rice syrup (also try 3/4), corn syrup (you may have to nearly double the amount), and malt syrup (about the same amount as brown rice syrup, but the result will be less sweet; try mixing in some stevia or maple syrup). For recipes calling for a cup of sugar, you can substitute with a liquid sweetener. As a guide, a cup of sugar is roughly equivalent to a cup of brown rice syrup in sweetness; reduce the total amount of other liquids in the recipe by about 1/4 cup for each cup liquid sweetener added. A good place on the internet to read more about sweeteners is www.vegsource.com/joanne/qa/qasweet.htm. A by-product in the creation of rose oil for perfume, rosewater is used in desserts in both the Middle East and South Asia.
Tub margarine vs. stick margarine? Vegans who won't eat butter may prefer margarine, but is margarine a good choice? Margarine is made from vegetable oils instead of animal fats, and has less saturated fats and no added cholesterol, good news for heart health. But margarine is more processed, and to solidify the oils, undergoes hydrogenation which creates trans-fatty acids, found to increase "bad" cholesterol (LDL) and lower "good" cholesterol (HDL).
In the late 1990s, some good tub margarines became available with no trans fats. I like to use these in my cooking. They typically come in 1 pound tubs and, because they are often 60-80% fat, just like margarine, can be substituted by weight. So, for example, a pound of margarine = 4 sticks = 32T = 2 cups; a pound of tub margarine should be substitutable 4 sticks of margarine. (If you need, say, 1 stick of margarine, try turning a tub upside down on the counter, letting it sit for a few minutes to soften a little, and open it, still upside down, setting aside the container and letting the margarine sit on the lid. Carefully slice through to quarter the tub, and take one of the quarters for your recipe.) Just one note of caution - if you use a low fat margarine or spread, some of the oil may be replaced with water. If you use a very soft spread that is less than 60% fat, baked goods like cookies may spread and be too soft and not very tasty. Stick with at least 60% fat spreads when enjoying desserts!