Start by preparing the cinnamon streusel. In a medium bowl, combine the flour, brown sugar, cinnamon, salt, and butter. Use a fork, your hands, or handheld electric mixer to mix until combined and the mixture is crumbly. Place the streusel into the refrigerator until ready to use.

Add the butter to a saucepan over medium-high heat. Allow to melt and brown, while stirring continuously (~5-8 minutes). As the butter continues to cook, you’ll notice that it starts to foam up across the surface (after about 2 minutes). Stir frequently to prevent the milk solids from burning. Continue cooking, stirring with a spatula, until the milk solids begin to brown and the color starts to deepen. Once the brown butter reaches a deep golden amber color and smells nutty, remove from the heat and immediately pour into a small bowl. Set aside to cool slightly.

In a medium bowl, whisk together the flour, sugar, baking powder, baking soda, and salt. Set aside.

In a separate large bowl, whisk together the buttermilk, eggs, and vanilla until well combined.

Add the dry ingredients to the wet, and whisk until just barely combined.

Add the slightly cooled brown butter and whisk until incorporated; be careful not to over-mix, you want a few small lumps in the batter! Let the batter rest at room temperature for 10-15 minutes.

Heat a large nonstick pan or griddle over medium heat. Grease with butter.

Remove the streusel from the refrigerator and If needed, use a fork or your hands to break it apart into crumbles.

For each pancake, sprinkle about 1-2 tbsp of the cinnamon streusel directly onto the pan. Use a medium cookie scoop or ¼ cup measuring cup to pour some of the pancake batter on top of the streusel. Dollop and press a few blueberries into each pancake. Then sprinkle another 1 tbsp of streusel on top of the batter.

Cook until little bubbles form on the surface, and then gently flip to cook the other side until golden brown (~2-4 minutes on each side). Once the pancake is flipped, add a little sprinkle of streusel on top of the cooked side so it melts into the pancake as it finishes cooking.

Transfer the cooked pancakes onto a baking sheet and keep warm in the oven at 200F while you make the rest of the pancakes.

Plate and serve the pancakes warm with a pat of butter, drizzle of maple syrup, and a hot cup of coffee, if desired.