CAKE: Peheat the oven to 350F. Generously butter a 10 in (9 cup) fluted tube pan; then springkle it with flour, tapping out the excess. Set aside. In a large bowl with the electric mixer on high speed, beat the butter until creamy. Gradually beat in the sugar and continue beating until the mixture is light and fluffy. Turn the mixer speed to low. Sift in the flour, baking powder, and salt. Beat just until the flour is absorbed. Beat in the Grand Marnier and orange zest. Beat in the eggs, one at a time, beating well after each addition. Add mini-chips. Spread the batter in the prepared pan, smoothing the top even. Bake until the cake shrinks from the side of the pan and a skewer inserted in the middle comes out clean, about 1 hour and 5 minutes. Let stand in the pan on a wire rack for 10 minutes, then carefully unmold the cake onto a second rack placed over a pieve of wax paper or aluminum foil. GLAZE: Meanwhile, combine the orange juice, Grand Marnier, and sugar in a small saucepan. Bring to a boil over moderate heat. Lower the heat and simmer until the mixture forms a light syrup, about 5 minutes. Then brush the syrup all over the warm cake. When it is cool, transfer it to a serving plate.