How to Make It
Preheat oven to 350°F. Line a baking pan with heavy-duty aluminum foil. Stir together brown sugar, marmalade, salt, pepper, and 1/2 cup of the orange juice in a small bowl.
Place ham sideways in prepared pan. Brush with 1/4 cup of the brown sugar glaze, gently pushing glaze in between slices using your hands or a brush. Turn ham over, and repeat process with an additional 1/4 cup of the glaze.
Turn ham cut side down in pan. Pour remaining 1/2 cup orange juice into bottom of pan. Cover tightly with aluminum foil.
Bake in preheated oven 1 1/2 hours. Uncover ham, and brush evenly with 1/3 cup of the glaze. Bake an additional 15 minutes. Brush with an additional 1/3 cup of the glaze. Bake until a thermometer inserted in thickest portion of ham registers 140°F, about 15 minutes. Remove from oven. Brush ham with remaining glaze and pan drippings. Let stand 15 minutes. Garnish ham with whole and sliced citrus.