1-Preheat the oven to 425 F, line: Preheat the oven to 425 F, line 12 count cupcake pan with paper liners ad set aside.
2-To make the crumb topping, stir together: To make the crumb topping, stir together flour, sugar, brown sugar, and salt. Add melted butter and whisk with a fork until coarse crumbs form. Set aside.
3-To make the lemon muffins mixture whisk: To make the lemon muffins mixture whisk dry ingredients (flour, baking soda, baking powder and salt) and set aside.
4-In a large bowl mix softened butter: In a large bowl mix softened butter and sugar for about 2 minutes at high speed. Add eggs, lemon zest, vanilla, and lemon extract and mix for 2 more minutes. Add Greek yogurt and lemon juice and mix just to combine. Running your mixer on low, mix in dry ingredients.
5-To make the cream cheese filling, mix: To make the cream cheese filling, mix softened cream cheese, sugar, and vanilla just to combine.
6-To assemble the muffins add 1 heaping: To assemble the muffins add 1 heaping Tablespoon of muffin mixture in each cup. Drop 1 Tablespoon of cream cheese mixture in the center of each muffin. Cover cream cheese filling with muffin mixture, filling each cup about 2/3 to 3/4 full.
7-Generously top each muffin with streusel crumbs: Generously top each muffin with streusel crumbs.
8-Place in preheated oven and reduce the: Place in preheated oven and reduce the temperature to 350 F. Bake 22-25 minutes, or until the tops are golden brown and the center has set.
9-Cool 5-10 minutes in the pan, then: Cool 5-10 minutes in the pan, then transfer the muffins on a rack to cool completely.
10-Meanwhile, prepare the glaze: Meanwhile, prepare the glaze. Stir powdered sugar with lemon juice. Start with 1 teaspoon of the juice and gradually add more until desired consistency has reached. Drizzle over muffins and serve.