Olive Oil and Saffron Pastry (Masa para empanadas)

From The New Spanish Table by Anya von Bremzen.
Ingredients:
1 tsp. active dry yeast
1/2 tsp. sugar
2/3 c. lukewarm water (105° to 115°F)
4 Tbsp. (1/2 stick) unsalted butter, melted
1/2 c. extra-virgin olive oil
1 large egg, beaten
1 large pinch of saffron threads, toasted, pulverized in a mortar, and steeped in 3 Tbsp. very hot water
2 scant tsp. salt
3 1/2 to 3 3/4 c. all-purpose flour

Place the yeast, sugar, and water in a large bowl, stir to mix, and let stand until foamy, about 10 minutes. Whisk in the butter, olive oil, egg, saffron, and salt, and mix well with a wooden spoon. Stir in 3 ½ cups of the flour, 1 cup at a time, stirring well after each addition.
Turn the dough out onto a floured work surface and knead until it is smooth and elastic, about 5 minutes, kneading in the remaining ¼ cup flour if the dough feels sticky. The dough will be oily and pliable. Divide the dough into two parts, one slightly larger than the other. Shape into two balls, place in a buttered bowl, cover loosely with plastic wrap, and let stand for 20 minutes. The dough will rise only slightly. The dough can be refrigerated, covered in plastic wrap, for up to 24 hours. Let it return to room temperature before using.
Makes enough dough for 1 large empanada. Used in Galician tuna empanada with melting onions.