1. Prepare dough. In a food processor, combine flour, salt, and turmeric, if using. Pulse to mix. Add butter, vinegar, and egg and pulse until crumbly. With the motor running, add water, 1 tsp. at a time, until a ball begins to form. Remove dough from processor. (Alternately, combine dry ingredients in a large bowl, cut in butter until crumbly, stir in egg and vinegar, then stir in water until combined.) Knead until smooth.
2. Divide dough into 4 equal pieces and form each into a log. Wrap in plastic wrap and refrigerate for at least 1 hour and up to overnight.
3. While dough chills, prepare filling. Heat oil in a large skillet over medium-low heat. Add onion and cook, stirring, until soft and fragrant. Add spinach and stir to heat through. Remove from heat and let cool about 10 minutes. If spinach mixture is liquidy, spoon into sieve lined with a double layer of paper towels and press down to drain.
4. In a large bowl, stir together salsa and 1 cup of the cheese. Stir in the spinach mixture.
5. Remove dough from refrigerator and cut each log into 5 equal pieces. On a floured surface, roll each piece into a 5-inch round about 1/8 inch thick. Keep finished rounds covered with a damp kitchen towel while preparing remaining rounds.
6. Preheat oven to 400 degrees F. Spray 2 baking sheets with vegetable cooking spray or line with parchment paper.
7. Fill empanadas by placing a large spoonful of filling on half of each dough circle. There may be extra filling. Pinch dough edges together, completely sealing entire empanada. Work from the edge and turn over 1/4 inch, pinch, and repeat, until entire edge is crimped and sealed. Place finished empanadas on prepared baking sheets.
8. Brush top of each empanada with beaten egg. Sprinkle a spoonful of the remaining 3/4 cup cheese on each empanada, pressing it lightly into the dough. Bake until firm and lightly golden, about 20 to 25 minutes. Cool empanadas on a wire rack for 5 minutes, then serve warm or at room temperature.
Source: Hannaford fresh Magazine, January - February 2014