Heat oven to 350°F. Grease 12-cup fluted tube (bundt cake) pan with shortening; lightly flour. In small microwavable bowl, microwave 2 ounces chocolate uncovered on High 1 minute. Stir; microwave in 30-second increments, stirring after each, until melted. Set aside to cool slightly.
In large bowl, beat 1 cup butter and the granulated sugar with electric mixer on medium speed until blended. Beat in melted chocolate. Add sour cream, orange peel, vanilla and eggs; beat until well blended. On low speed, beat in remaining cake ingredients. Spread batter in pan.
Bake 30 to 40 minutes or until toothpick inserted in center comes out clean. Cool 15 minutes. Remove from pan to cooling rack. Cool completely, about 1 hour.
In 1-quart saucepan, heat 1 ounce chocolate and 2 tablespoons butter over low heat 2 to 3 minutes, stirring occasionally, until melted. Remove from heat. With wire whisk, beat in powdered sugar and 1 tablespoon of the orange juice. Beat in additional orange juice, 1 teaspoon at a time, until glaze is smooth and consistency of thick syrup. Drizzle glaze over cake, allowing some to run down side. Garnish with orange peel strips.