In a large bowl, beat the eggs. Add the baking soda and 2 1/2 cups of flour, mixing well to form a firm dough. If the dough is too sticky, add more flour.
Sprinkle a little flour over a work surface or pastry board and the rolling pin. Separate the dough into 5 pieces and roll out each piece in paper-thin strips.
Heat the oil in a deep frying pan.
Cut the large strips into strips two-inches wide and about 12-inches long, and prick the dough with a fork. Carefully begin wrapping the strip around the prong of a wide two-prong fork while frying it. This forms a "rose." Keep rolling (or coiling) it around itself as it fries and fry until lightly browned. Remove from the oil and drain in paper-towel lined colander.
Repeat with remaining dough.
Prepare the syrup by combining the sugar, 1 1/2 cups of water, lemon juice, orange-flower water, and vanilla together in a pan. Just cover the mixture with water and simmer over low heat for 45 minutes to thicken the syrup. Stir and remove from the heat.
Use immediately or set aside for later use.
Dip the debla into the heated syrup, soaking it well, and drain in a colander. If the syrup becomes too thick, add 1 or 2 tablespoons of warm water.
Place the debla on a platter and serve.
Sheilah Kaufman is the food editor of Jewish Women International's (JWI) website www.jwmag.org and a contributing food editor for The Town Courier, and contributing food writer to Vegetarian Times Magazine and The Washington Post.