Pre-heat oven to 350F (180C). Grease and flour a 6 medium size muffin tin.
FOR THE TOPPING
In a small bowl mix together the flour and sugar add the butter and mix with a fork, pastry cutter or even clean hands to form coarse crumbs, set aside.
FOR THE MUFFINS
In a medium bowl beat with a fork, the egg, milk and oil until well combined.
In a large bowl whisk together the flour, baking powder, salt, zest and sugar. Make a well in the centre and add the beaten egg mixture and lemon juice, mix just until flour is wet, about 15-16 stirs, no more.
Spoon the batter into the prepared muffin pan, ( I made 5 muffins but I like to fill my pan). Top with the crumb topping and bake for about 18-25 minutes. Let cool about 10 minutes before removing from pan. Enjoy!
Notes
We found the lemon taste enough but if you want a stronger taste then add extra zest or even some lemon extract to the batter. The muffins can be stored in an airtight container and kept for up to 2 days at room temperature. To store them in the fridge place them in an airtight container, place a paper towel on the bottom of the container, the muffins on top and again a paper towel on top of the muffins. This will absorb any moisture. They will last up to 1 week in the fridge. You can also freeze them, place the muffins in a freezer safe bag or container. They will keep up to 2 months in the freezer. They can be thawed on the counter.