Preheat the oven to 350 degrees F. Grease and flour a 9x5-inch loaf pan. Set the pan off to the side for later.
In a medium bowl, whisk together flour, sugars, baking powder, salt, and cinnamon.
Melt butter in a small saucepan over medium/high heat until it stops crackling and turns brown. Once it is browned, remove from the heat and place off to the side to cool.
In a separate medium bowl, whisk together egg, yolk, milk, and vanilla. Once the butter has cooled, slowly pour it into the bowl while whisking continuously. Make sure to use a rubber spatula to get all the brown bits out of the pan. Whisk until well incorporated.
Add the wet ingredients to the dry ingredients. Fold together. Once no flour remains, add in the blueberries and fold until well incorporated. Add the batter to the loaf pan.
To make the topping, combine all the ingredients in a small bowl. Use your fingers to blend all the ingredients together until they are about the size of oats. Sprinkle the topping all over the top of the batter.
Bake the cobbler bread for 55 to 65 minutes until fully risen and a toothpick inserted into the center comes out clean.