Preheat oven to 425°F. Prepare a muffin tin with liners and set aside.
First, make the streusel crumble: Combine the two sugars, salt, and flour in a small bowl, and then slowly whisk the melted butt into the mixture with a form. Set aside.
Then, make the blueberry glaze: combine 1 cup blueberries with 1 teaspoon granulated sugar in a small saucepan over medium high heat. Mash the blueberries with a potato masher (or the back of a spoon) and bring the mixture to a simmer. Simmer, stirring frequently, for about 5 minutes until combined and broken down, then remove from heat. Be careful not to overcook.
Finally, the muffins: In your biggest bowl, whisk together the flour, baking powder, and salt. In a separate bowl, whisk together the eggs and sugar, and then the browned butter and oil. Mix in the milk. Fold the egg mixture into the dry ingredients, adding the remaining 1 cup blueberries and fresh lemon zest as you do so. Mix until just combined.
Fill the each muffin cup about 2/3’s full with batter. Spoon 1 teaspoon of blueberry glaze on top of each, and swirl it around to cover the top of the batter with a toothpick (or fork). Sprinkle the streusel on top of each muffin. Bake for 20-25 minutes, remove from oven, and let cool.