In a medium saucepan over medium heat, melt the salted butter until it becomes golden brown and has a nutty aroma, about 5-7 minutes. Allow to cool slightly.

In a large mixing bowl, whisk together the cooled brown butter, granulated sugar, brown sugar, eggs, Greek yogurt, sourdough discard, and vanilla extract until smooth.

In a separate bowl, sift together the all-purpose flour, baking powder, baking soda, and salt. Gently fold this mixture into the wet ingredients until just combined.

In a small bowl, combine brown sugar and cinnamon for the swirl and set aside.

Preheat oven to 350°F (175°C). Spoon batter into the mini bundt pans one-third full, add a layer of cinnamon-sugar, then fill three-quarters full with batter.

Bake for 15-20 minutes or until a toothpick comes out clean. For a loaf pan, bake for 40-50 minutes.

While baking, beat together cream cheese, powdered sugar, and milk until smooth for the drizzle.

Cool the bundts for 5 minutes before inverting onto a wire rack, then drizzle with the cream cheese mixture.