Lightly grease 2 9x5 inch loaf pans. Line a broiler pan with foil. Place saffron on foil and spread thinly. Place pan under a very low broiler and gently dry saffron (do not discolor) 3-4 minutes or until dry. Place saffron in a small bowl and crush to a fine powder. Add boiling water and let stand 8 hours. Dissolve 1 teaspoon of sugar in quarter cup warm water. Add yeast, whisk and let stand 10-15 minutes or until frothy. Put flour, salt, lard and butter into a bowl and cut in finely. Mix in remaining sugar and currants. Stir saffron into remaining warm water and add to flour mixture. Stir in yeast and mix to form a dough. Knead lightly, cover and let rise in a warm place until double in bulk. Knead dough and divide in half. Press each piece to a rectangle with width equal to length of loaf pan. Roll up dough, jellyroll style, and place in greased loaf pans, seam side down. Press to fill corners. Cover and let stand at room temperature until dough has risen to top of pans. Preheat oven to 375'F. (190'C.). Bake in preheated oven 35-45 minutes or until golden. If necessary, cover with foil during baking to prevent overbrowning. Cool on a wire rack. Let stand 1 day before serving. Makes 2 cakes.