Proofing the yeast: Stir together yeast, a pinch of sugar and lukewarm water in a small bowl and let stand until bubbly, 5 to 10 minutes. (If the mixture doesn't foam, discard and start over with new yeast.)
In a medium saucepan, heat milk with 6 tablespoons butter and granulated sugar over low heat, stirring, until mixture is warm (105 to 115°F), butter is melted, and sugar is dissolved.
Next, in the bowl of your stand mixer, sift flour and salt into it. Make a well in the flour and add the proofed yeast mixture. Fix the paddle attachment, next add in the warm milk in a slow stream, mixing at low speed. Increase speed to medium, add in eggs 1 at a time, then the raisins and orange zest. Continue beating until dough is smooth and elastic, about 5 minutes. The dough will be very sticky. Do not add any extra flour.
Grease kugelhopf mold/ standard bundt pan with the remaining tablespoon butter. If using almonds, then add now in each depression of the pan. Then scrape spoonfuls of dough evenly into mold (dough will be very elastic). Cover the bundt pan with a kitchen towel and let the dough rise in a warm place until it rises to the top of the pan, (about 2 hours).
Preheat oven to 400°F.
Remove towel from kugelhopf. Bake in the middle rack of the oven for 15 minutes, then loosely cover bundt pan with foil and continue to bake until golden and a tester inserted in center comes out clean, 20 to 25 minutes more. (Took me 10 minutes more, covered with a foil). Transfer the bundt pan to a wire rack, cool in the pan for 2 minutes, then invert kugelhopf onto a rack to cool completely, about 1 hour. Dust with confectioners sugar.