In small bowl, pour rum over raisins. Set aside to soak.
In large mixing bowl, combine 2-1/2 cups of flour and yeast. In small saucepan, combine milk, 2/3 cup butter, 1/2 cup granulated sugar, vanilla sugar (if using), and salt. Heat and stir until warm (120 degree F to 130 degree F) and butter is almost melted. Add to the flour mixture with vanilla (if using). Beat with electric mixer 30 seconds, scraping bowl. Beat 3 minutes.
Drain raisins and add to dough with almonds and lemon. Stir in as much remaining flour as you can with a spoon.
Turn onto a floured surface. Knead in enough remaining flour to make a moderately soft dough thats smooth and elastic (3 to 5 minutes). Shape into a ball. Place in a grease bowl; turn once to grease the surface. Cover; let rise in a warm place until doubled in size (about 1 hour).
Grease 2 baking sheets; set aside. Punch dough down. Divide dough in half; turn onto a floured surface. Cover; let rest 10 minutes. Form each half into a 9x3-1/2-inch loaf and place on prepared baking sheets. Flatten slightly to form 10x4-inch loaves. With the side of your hand, make an indentation lengthwise down the to center of each loaf.
Bake in a 350 degree F oven 40 to 45 minutes or until golden and bread sounds hollow when you tap it. Remove; place on a wire rack. Brush with the melted butter. Combine 1 tablespoon granulated sugar and the powdered sugar; sprinkle over loaves and cool.
For vanilla sugar, split 2 vanilla beans lengthwise in half. Place in a covered container with 1 pound granulated or powdered sugar. Cover; let stand for 1 week.