Preheat oven to 375 degrees. Line a muffin pan (or pans) with baking liners.
In a small bowl, combine the flour, sugar, salt, melted butter, and lemon zest; cut together with a fork until crumbly. Set aside.
In a large bowl, whisk the flour, baking soda, and salt. Set aside.
In another large bowl, using a hand mixer or stand mixer fitted with the paddle attachment, mix the eggs until frothy.
Add in the sugar and oil; mix until combined.
Add in the Greek yogurt, lemon zest, lemon juice, and vanilla; mix until combined.
Pour in the flour mixture and fold together with a spoon or spatula; don’t over mix.
Scoop the batter into the prepared muffin pan, filling the cups ¾ of the way full. Top each batter filled cup with the crumble topping.
Bake for 20 minutes, or until a toothpick inserted into the middle comes out clean. Cool for a few minutes in the pan and then move to a cooling rack until fully cooled.
Pour the powdered sugar into a small bowl, add 4 tablespoons of lemon juice and mix until the lumps are dissolved.If the mixture is too thick, add another tablespoon of lemon juice until the desired consistency has been reached.
Spoon the glaze over the muffins. Allow the the glaze to set before serving or storing.
VariationsSour cream instead of yogurt.Lemon extract. These lemon crumb muffins are super lemony BUT if you want even more lemon flavor you can add 1/4 teaspoon to the muffin batter too.Add blueberries or raspberries. Toss some berries in a little bit of flour (this keeps them from sinking) and add them for a lemon blueberry muffins or lemon raspberry muffins. Add after adding the flour to the batter (last step).Lemon poppy seed muffins. Stir in some poppy seeds after combining the dry ingredients and wet ingredients for moist lemon poppy seed muffins.How to StoreLine an airtight container with a paper towel. Store the muffins in a single layer at room temperature for 4 days or in the refrigerator for up to 1 1/2 weeks.