1-Start by heating 1 and 1/3 cups milk until lukewarm, then mix it with 1 tablespoon active dry yeast, 2 tablespoons sugar, and 1 cup flour in a large bowl. Let this blend sit in a warm spot for 30 minutes until it rises about 1.5 times, or up to 1 hour at room temperature, then stir lightly.

2-Next, melt 1 stick of butter until just melted and add it to the mixture along with 2 large eggs, the remaining sugar, 1/2 teaspoon vanilla extract, and 1 cup flour. Whisk everything together for a smooth batter. Using a dough hook on your mixer at speed 2, incorporate the remaining 2 cups flour in half-cup increments and mix for 15 minutes until the dough is soft and slightly sticky but not clinging to your fingers or the bowl.

3-Letting the Dough Rise: Transfer the dough to a large bowl, cover it, and let it rise in a warm spot for 2.5 hours until it grows 3-4 times in size. While the dough rises, prepare the poppy seeds by rinsing 1 cup poppy seeds multiple times with water. Add 3 cups water, bring to a simmer without boiling, cover, and let sit for 30 minutes. Simmer again and repeat the process for another 30 minutes, then drain using cheesecloth or a fine mesh sieve.

4-Grind the seeds with a food grinder or coffee grinder in small batches, applying firm pressure, and mix with 8 ounces sweetened condensed milk. For assembly, line a cookie sheet with parchment paper and divide the dough into 4 portions. Roll each into an 11-inch by 8-inch oval, spread 1/2 cup poppy seed mixture over each, and sprinkle with 1/4 to 1/3 cup raisins (about 30-40 per portion).

5-Baking and Finishing: Gently roll each into a roulade shape and place on the sheet. Brush with an egg wash made from 1 egg white, 1/2 teaspoon sour cream, and 1/2 teaspoon sugar. Let rise at room temperature for 1 hour or in a 100-degree Fahrenheit oven for 30 minutes. Preheat the oven to 360 degrees Fahrenheit and bake for 28-30 minutes until deep golden.