Pound Cake with Macerated Orange in Grand Marnier

For cake:
2 cups all-purpose flour
1/2 teaspoon baking powder
1/4 teaspoon salt
2 sticks (1 cup) unsalted butter, softened
1 1/2 cups sugar
3 large eggs, at room temperature for 30 minutes
1 teaspoon finely grated fresh lemon zest
1 teaspoon vanilla
1/2 cup whole milk, at room temperature

For orange Grand Marnier:
6 oranges
1 Grand Marnier
1 cup sugar

Special equipment: a 9- by 5- by 3-inch metal loaf pan

Directions:

For cake:
1. Put oven rack in middle position and preheat oven to 350°F.
2. Generously butter and flour loaf pan, knocking out excess flour.
3. Whisk together flour, baking powder, and salt.
4. Beat together butter and sugar in a large bowl with an electric mixer at medium-high speed until light and fluffy, about 3 minutes in a stand mixer or 5 with a handheld.
5. Add eggs 1 at a time, beating well after each addition, then beat in zest and vanilla.
6. Reduce speed to low and add flour mixture and milk alternately in batches, beginning and ending with flour and mixing until just incorporated.
7. Spoon batter into loaf pan and bake until golden and a wooden pick or skewer inserted in center comes out with crumbs adhering, 1 to 1 1/4 hours.
8.Cool cake in pan on a rack 30 minutes, then invert onto rack and cool completely.

For Orange Grand Marnier:

1. Cut the orange in very thin slices with the skin on (this will bring more aroma) add some sugar to taste and grand Marnier and let macerated at least few hours(it is even better to make it 24hours for better maceration).
2. Spoon oranges and syrup over slices of cake just before serving.