We replicated the flavor profile of Mexican chocolate using semisweet chocolate and cinnamon. If you prefer to use Mexican chocolate, look for it with the hot drink mixes or on the Hispanic food aisle. This moist pound cake is equally delicious without the sauce.
Preheat oven to 325°. Microwave chocolate baking squares in a microwave-safe bowl at HIGH 1 minute and 15 seconds or until chocolate is melted and smooth, stirring at 15-second intervals. Beat butter at medium speed with a heavy-duty electric stand mixer 2 minutes or until creamy. Gradually add granulated sugar, beating 5 to 7 minutes or until light and fluffy. Add eggs, 1 at a time, beating just until yellow disappears after each addition. Stir in melted chocolate, chocolate syrup, and vanilla until smooth.
Combine flour and next 3 ingredients; add to butter mixture alternately with buttermilk, beginning and ending with flour mixture. Beat at low speed just until blended after each addition. Pour batter into a greased and floured 10-inch (14-cup) tube pan.
Bake at 325° for 1 hour and 10 minutes or until a long wooden pick inserted in center of cake comes out clean. Cool in pan on a wire rack 10 to 15 minutes; remove from pan to wire rack, and let cool completely (about 1 hour and 30 minutes). Sprinkle with powdered sugar, if desired. Serve with Mexican Chocolate Sauce. Garnish, if desired.
*2 (4-oz.) packages Mexican chocolate, chopped, may be substituted. Omit ground cinnamon.
Note: We tested with Nestle Abuelita Marqueta Mexican chocolate.