For the Dough:

1. In a small bowl, combine warm milk and sugar. Sprinkle the yeast over the top and let it sit for 5-10 minutes until frothy.

2. In a large bowl, combine the melted butter, salt, and egg. Add the yeast mixture and mix to combine.

3. Gradually add flour, 1/2 cup at a time, mixing until a soft dough forms. Knead the dough on a lightly floured surface for about 5-7 minutes until smooth and elastic.

4. Place the dough in a lightly greased bowl, cover with a clean towel, and let it rise in a warm place for 1-1.5 hours or until doubled in size.

For the Lemon Filling:

1. In a small bowl, combine softened butter, granulated sugar, lemon juice, lemon zest, and salt. Stir until smooth and well combined.

Assembling the Rolls:

1. Once the dough has risen, punch it down and roll it out on a lightly floured surface into a 12×9-inch rectangle.

2. Spread the lemon filling evenly over the dough, leaving a small border around the edges.

3. Starting from one edge, carefully roll the dough into a tight log. Slice the log into 12 even rolls and place them in a greased 9×13-inch baking pan.

4. Cover the pan with a towel and let the rolls rise for another 30 minutes, or until they’ve puffed up.

Baking the Rolls:

1. Preheat your oven to 350°F (175°C).

2. Bake the rolls for 20-25 minutes, or until golden brown on top and cooked through. Let them cool slightly before glazing.

For the Lemon Glaze:

1. In a small bowl, whisk together powdered sugar, lemon juice, milk (or cream), and vanilla extract (if using) until smooth.

2. Drizzle the glaze over the warm rolls, allowing it to soak in slightly.