1. Preheat the oven to 375°F (190°C).
2. In a large bowl, combine flour, sugar, salt, and baking powder.
3. In another bowl, mix melted butter, milk, egg, lemon zest, and lemon juice.
4. Pour the wet ingredients into the dry ingredients and mix until just combined.
5. Turn the dough onto a floured surface and roll it out into a rectangle about 1/2 inch thick.
6. Roll the dough tightly from one edge to the other to form a log.
7. Cut the log into 12 equal pieces and place them in a greased baking dish.
8. Bake for 20-25 minutes or until golden brown.
9. For the glaze, mix powdered sugar with lemon juice until smooth, then drizzle over warm rolls.