
This Sourdough Coffee Cake made in a bundt pan is a delicious sour cream breakfast cake with a thick ribbon of cinnamon sugar and walnuts swirled in the middle.
Preheat the oven to 350F degrees.
In a large mixing bowl, beat together sugars, oil, and eggs until smooth with a whisk.
Then add the sour cream, vanilla, and sourdough discard, and stir until combined.
In a separate medium bowl mix together the baking soda, salt, and flour.
Fold the dry ingredients into the wet ingredients until just moistened. It’s ok if it is lumpy. Don’t overmix because this will cause a tougher texture.
In a separate bowl, mix together cinnamon, sugar and chopped nuts.
Heavily spray a bundt cake pan with non-stick spray ensuring to get the inner and outer rims. You can brush oil on the pan instead but I wouldn't recommend greasing the pan with butter as the milk solids can act like glue.
Pour half of the cake batter into the pan and sprinkle the cinnamon sugar mix on top (it’s a thick layer). Using a toothpick swirl the cinnamon sugar and then pour the remaining batter on top.
Bake for 50-60 minutes. To ensure the coffee cake is done, place a toothpick in a few spots around the coffee cake. If the toothpick comes out clean, then it is ready to be removed from the oven.
Once baked, let the coffee cake sit for 5-10 minutes in the pan to set before placing on a cooling rack. I don’t recommend letting it completely cool in the pan as that can make the edges tough. Take a spatula and gently run it along the sides of the pan to ensure the coffee cake quickly releases from the pan when flipped. Place a cooling rack on top of the bundt pan and carefully flip the bundt pan over. Give the pan a shake from side to side to gently release the cake from the pan.
Prepare the icing by whisking together the powdered sugar and milk. Slowly add the milk until you reach your desired consistency.
Top with a mix of sugar and chopped walnuts if desired.