In a large bowl, combine the sugar and lemon zest and use your fingers to rub them together to release the oils from the lemon zest.

In a separate bowl, whisk together the flour, baking powder, baking soda, salt and poppyseeds in a medium bowl and set aside.

Add in the oil to the sugar and lemon zest and whisk until they're combined.

Then add in the eggs and mix for 1-2 minutes until the color lightens a little.

Add the greek yogurt and mix until the batter is smooth.

Fold in the dry ingredients just until barely combined. 

Add the lemon juice and fold until the batter is smooth.

Cover the batter with a towel and allow it to rest for 30-60 minutes. Preheat oven to 425F (218C) and line 12 tins of a muffin pan

For the streusel, combine all the ingredients in a bowl and use a pastry cutter, a fork or your fingers to combine the butter into the sugar and flour. You want to make pea size chunks of streusel.

Distribute the streusel evenly over the muffins (it may look excessive but as the muffin bakes, it grows in surface area).

Place the muffins in the oven at 425F/218C convection (or 400F/204C conventional) for 5 minutes and then lower the heat to 350/177C convection (or 325F/162C conventional) for 10-12 minutes.

Remove the muffins from the oven and let them cool in the pan for a few minutes while you make the glaze.

To make the glaze, combine the lemon juice and the sugar in a bowl and whisk it for 1-2 minutes until it's completely smooth.

Move muffins to a wire rack and drizzle the glaze on top or dunk the muffins in the glaze (if there's not streusel).