Preheat oven to 375 degrees F. Lightly grease 12 muffin cups, or line with muffin liners.
In a medium bowl, whisk together eggs, yogurt and vanilla.
In another mixing bowl, mix together flour, sugar, baking soda and salt. Add butter one piece at a time. Mix until resembles moist crumbs.
Add the wet ingredients to the dry ingredients and stir it all together just until combined. Batter should be lumpy. Scoop the batter into the muffin tin. It should fill each cup about 3/4 full.
For the Cinnamon Crumb :
In a large mixing bowl, whisk together sugar, cinnamon, salt and flour. Add melted butter and stir in until it all comes together.
Fluff with a fork to make a mixture that resembles coarse crumbs. Set aside.
Sprinkle the topping on top of the batter of each muffin. It may seem like it's a lot of topping but try your best to use it all up.
Bake the muffins for 20 minutes or until the toothpick inserted into each muffin comes out clean.
Let the muffins cool in the pan for 10 minutes, then transfer onto a cooling rack to cool completely. Store in an airtight container for up to 2 days.