Preheat oven to 400° F and line your muffin tin with liners.
To make the crumb topping: whisk together flour, sugar and cinnamon. Add melted butter and stir until crumbly. Refrigerate until ready to use.
To make the muffins: stir together flour, baking powder and salt. Set aside.
In another bowl, place ⅔ sugar and lemon zest and rub for a minute. Add eggs and whisk with the lemon/sugar until combined.
Whisk in yogurt, oil, lemon juice and vanilla extract.
Fold wet ingredients into dry ingredients and whisk everything together.
Fold the blueberries gently into the batter. NOTE: Reserve ½ cup of blueberries for the topping.
Spoon the batter into the muffin tin, filling each ⅔ full. Cover each muffin with the remaining blueberries and crumb top.
Place in the oven for 5 minutes then reduce the oven temp to 375° F and bake for about 15-20 minutes until the middle is cooked.
Cool for 5 minutes in the pan the remove muffins to cool on a wire rack.