In a small bowl, dissolve 2½ teaspoons of active dry yeast in ¾ cup of warm milk mixed with 2 tablespoons of granulated sugar. Allow to foam for 5-10 minutes.

In a large mixing bowl, combine 4 cups of all-purpose flour, 1 teaspoon of salt, ⅓ cup of unsalted butter, 2 large eggs, 1 teaspoon of vanilla extract, and the zest of one lemon. Pour in the yeast mixture and blend until a dough forms.

Turn the dough onto a floured surface and knead for 10-12 minutes until smooth and elastic.

Let the dough rise in a warm area for 1 to 1.5 hours, or until it doubles in size.

In a medium saucepan over low heat, combine ¾ cup of raspberry preserves with 1 tablespoon of cornstarch and 2 tablespoons of water. Stir until thickened, about 5 minutes.

Once the dough has risen, punch it down gently and roll out into a rectangle about ¼ inch thick. Spread the cooled raspberry filling across the surface.

Starting from the long edge, roll the dough tightly into a log. Slice the log lengthwise to reveal the layers. Twist the two halves together.

Place the twisted loaf into a greased 9x5 inch loaf pan and cover it loosely. Let it rise for another 30-45 minutes.

Preheat the oven to 350°F. Brush the top with melted butter and bake for 35-40 minutes until golden brown.

Let the loaf cool in the pan for 10 minutes, then transfer to a wire rack. Mix 1 cup of powdered sugar with 2 tablespoons of lemon juice to create a glaze and drizzle over the loaf.