Brown butter over medium-high heat until foamy and golden; set aside to cool
In a large bowl, combine all wet ingredients along with brown and white sugar; mix until smooth
Add dry ingredients to wet mixture and fold in until well combined
Set aside for 30 minutes to allow flour to hydrate
In a small bowl, combine streusel ingredients and work in butter until coarse crumbs form
Grease and line an 8x8 pan
Add half of batter to pan and top with generous layer of streusel
Add remaining batter and finish with another layer of streusel
Bake at 375°F for 45-60 minutes
While baking, combine glaze ingredients in a small bowl and mix until smooth
Once coffee cake is done baking, drizzle with glaze and enjoy
