In a small bowl, combine warm milk, 1 tablespoon of sugar, and yeast. Let it sit for about 5-10 minutes until frothy.
In a large mixing bowl, whisk together the remaining sugar, eggs, and vanilla extract. Add the yeast mixture and mix until combined.
Gradually add flour and salt, mixing until a dough forms.
Knead the dough on a floured surface for about 8-10 minutes until smooth and elastic.
Incorporate the softened butter, kneading until fully combined.
Place the dough in a greased bowl, cover with plastic wrap, and let it rise in a warm place for about 1-2 hours, or until doubled in size.
While the dough is rising, prepare the raspberry swirl by combining raspberries, raspberry jam, and lemon juice in a small saucepan over medium heat. Cook for about 5 minutes until the raspberries break down. Remove from heat and let cool.
Once the dough has risen, punch it down and roll it out on a floured surface into a rectangle about 1/2 inch thick.
Spread the raspberry mixture evenly over the dough.
Roll the dough tightly into a log, pinching the seams to seal. Place the log seam-side down in a greased loaf pan.
Cover the loaf with a kitchen towel and let it rise again for about 30-45 minutes.
Preheat the oven to 350°F. Bake the loaf for 25-30 minutes, or until golden brown and a toothpick inserted comes out clean.
Let it cool in the pan for 10 minutes before transferring to a wire rack to cool completely.