Preheat the oven to 375°F and line a 12-cup muffin tin with paper liners.
Make the streusel: stir the flour, brown sugar, cinnamon and salt with the melted butter until large clumps form. Refrigerate while you make the batter. In a small bowl, mix the brown sugar and cinnamon for the cinnamon layer.
In a large bowl, whisk together the flour, baking powder, baking soda and salt.
Blend the cottage cheese, eggs, sugar, melted butter, milk and vanilla until smooth and creamy, 30-45 seconds. The blended cottage cheese works just like sour cream, giving a tender, moist, classic coffee cake crumb.
Pour the wet mixture into the dry ingredients and fold just until combined.
Spoon about 1 heaping tablespoon of batter into each cup and sprinkle with the cinnamon layer. Top with the remaining batter, filling the cups almost to the top.
Pile the streusel generously over each muffin and press it in lightly so it sticks. Bake for 20-24 minutes, until the streusel is golden and a toothpick inserted in the center comes out clean.
Cool for 15 minutes. Whisk the powdered sugar, milk and vanilla into a thick glaze and drizzle over the muffins.