In a medium bowl, use a pastry cutter to cut butter into flour til pieces are pea-sized. In small bowl, stir together the egg yolk and sour cream, then stir into flour mixture til all the dough is moistened. Gently knead the dough just til a ball forms. Wrap dough with plastic wrap and refrigerate for several hours til firm. Divide dough into 4 portions. On a well-sugared surface, use your hands to slightly flatten the dough. Roll dough from center out to edges, forming a 10" circle. Repeat with rest of dough, making sure you re-sugar your surface well! Turn each dough circle over. (So they are sugar side-up.)
In medium bowl, combine preserves, coconut, almonds and vanilla and almond extracts well. Just use a spoon, but stir well. Spread thin layer of the mixture thinly over each circle. With a pizza wheel, cut each circle into 12 wedges just like you were cutting a pizza. Roll each wedge up (loosely), beginning with the wide end, and roll towards the pointed end. (Just like you do crescent rolls.) Place all point-side down onto cookie sheets lined with parchment paper. (Parchment paper is a must, you'll thank me later!) Sprinkle all with sugar. Bake at 350 degrees for 17 minutes or til just set and very lightly browned. Immediately and carefully remove with a sharp spatula to wire racks to cool. They will set completely as they cool. Makes 48 sweet, buttery, flaky crescent cookies.