Preheat oven to 350 degrees. Grease a bundt pan very well, set aside.
In a small bowl, whisk together flour and baking soda.
In a separate bowl, beat vegetable oil and sugars together. Pour in melted butter and cocoa powder and mix until combined. Add eggs and sour cream and stir until fully incorporated. Add flour in two additions alternating with the stout. Beat until smooth, about 1 minute. Pour into prepared bundt pan and bake for 45-47 minutes OR until a toothpick inserted in the center comes out clean. Release the sides of the cake with a butter knife and allow cake to cool in pan for 20 minutes before inverting onto a wire rack to finish cooling completely. While cake is cooling, prepare chocolate glaze.
In a microwave-safe bowl, heat heavy cream and butter for 1 minute in the microwave. Pour in chocolate chips and wiggle the bowl so they are all immersed into the cream. Allow to sit for 3 minutes before stirring into a smooth consistency. Stir in corn syrup. Allow glaze to cool to room temperature before drizzling on cooled bundt cake.
Guinness Chocolate Stout Cake will stay fresh and moist for up to 6 days stored in an airtight container.