1. In a bowl, add yeast and 1/2 teaspoon granulated sugar to 2 tablespoons warm (110°) water. Let stand until yeast is soft, about 5 minutes.
2. Cut vanilla bean lengthwise; scrape out black seeds and add to vodka in a cup. Add saffron to milk in another cup.
3. In another bowl, beat to blend remaining granulated sugar, butter, and salt.
4. Add yeast mixture, vodka-vanilla mixture, saffron mixture, eggs, 2 1/4 cups flour, and orange peel. Stir until thoroughly moistened.
5. With mixer on high speed, beat dough until stretchy and shiny, 4 to 5 minutes. Stir in 1/4 cup flour until evenly moistened.
6. With a dough hook, beat on high speed until dough pulls fairly cleanly from sides of bowl, about 2 minutes. Dough will be soft and slightly sticky to touch. If necessary, add more flour, 1 tablespoon at a time, and beat longer.
Or with lightly oiled hands, knead dough in bowl until it feels smooth, pulls from your hands, and is just slightly sticky to touch, about 4 minutes. If necessary, add more flour, 1 tablespoon at a time.
7. Cover bowl with plastic wrap and let dough rise in a warm place until about doubled in volume, 1 to 2 hours.
8. Line the bottom of 1 juice or broth can (46-oz. size) with cooking parchment cut to fit. Then line sides of can with parchment, extending it about 2 inches above can rim; secure with paper clip. (Or use waxed paper, buttered heavily and dusted with flour.)
9. Punch dough down to expel air, then shape into a smooth-topped ball and drop into can. Cover can lightly with plastic wrap and let stand in a warm place until dough is about 1 1/2 inches below can rim, 45 minutes to 1 1/4 hours.
10. Bake on lowest rack in a 325° oven until a long, thin wood skewer inserted into center of the loaf comes out clean, 1 1/4 to 1 1/2 hours (45 minutes to 1 1/4 hours at 300° in a convection oven).
11. Let bread stand in can for 10 minutes, then remove from can and parchment. Lay the loaf on its side on a rack to cool.
12. Blend powdered sugar with lemon juice and 3/4 teaspoon water until smooth. Stand kulich upright and drizzle top with icing.
13. To serve, cut bread into rounds.