Turtle Fudge skillet cake

My favorite dessert when I was a consultant for Pampered Chef. So yummy.
Ingredients:
1 package (18.25 ounces) devil's food cake mix (plus ingredients to make cake)
1 tablespoon butter or margarine
4 squares (1 ounce each) semi-sweet chocolate for baking
1 jar (12.25 ounces) caramel ice cream topping, divided
1/2 cup pecans, chopped
Vanilla ice cream or thawed, frozen whipped topping (optional)
Directions:
1. Preheat oven to 350 F. Prepare cake mix according to package directions in a bowl; beat until smooth. Melt butter in a skillet over medium heat, tilting skillet to coat bottom. Gently pour batter over bottom of skillet, spreading evenly.

2. Bake, uncovered, 30-35 minutes or until cake tester inserted in center comes out clean. Carefully remove to cooling rack. Loosen edges of cake and carefully invert cake onto heat-proof serving plate.

3. Chop chocolate. Combine half of the caramel topping with chocolate in a bowl. Microwave, uncovered, on HIGH 30-60 seconds or until melted. Stir until smooth. Carefully spread caramel fudge glaze over cake.

4. Chop pecans; sprinkle evenly over glaze. Drizzle with remaining caramel sauce, if desired. Serve with vanilla ice cream or whipped topping.