Preheat oven to 350 degrees. Greased a 10" bundt cake pan with shortening, then dust with flour. (Or use our cake release)
Using a hand mixer, mix the butter, sugar and vanilla until fluffy. Add eggs and beat well.
In another bowl, whisk together the flour, 1 teaspoon baking soda and salt.
Add the flour mixture, alternating with the buttermilk to the butter mixture, beating until well combined.
Measure out 2 cups of batter in a small bowl, stir in the syrup and remaining ¼ teaspoon baking soda. Mix well then set aside.
Pour the plain batter into the bundt pan first and then pour the chocolate batter on top. Do not mix together.
Bake for 60-65 minutes, until a toothpick comes out clean. Cool for 15 minutes in the pan, then turn the cake out onto a wire rack to cool completely.
For the Glaze:
In a small bowl, whisk together the glaze ingredients; slowly add the milk 1 tablespoon at a time until you reach the desired consistency for drizzling a thick glaze. Drizzle the glaze on the cake to decorate.
Store the cake in an airtight container at room temperature.
The calories shown are based on the cake being cut into 12 pieces, with 1 serving being 1 frosted slice of cake. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate.