Preheat the oven to 425F degrees. Line a 12 cavity muffin pan with muffin papers or grease & flour the cavities. Set aside.

In a large bowl using a hand held or stand mixer, beat the butter and sugar together on medium speed until light and fluffy. Add in the eggs, vanilla and continue beating until combined - about 30 seconds. Turn off the mixer and scrape down the sides of the bowl. Add in the lemon zest, lemon juice & yogurt and beat on low speed until combined.

In a separate large bowl, whisk together the flour, baking powder, salt & poppy seeds. Using a large wooden spoon or rubber spatula, carefully fold the flour mixture into your wet ingredients until just combined.

Spoon the batter into your muffin cavities, filling them to the very top. Bake for 5 minutes at 425F then turn down the oven to 375F and continue baking for 11-13 minutes until an inserted toothpick comes out clean. Do not take the muffins out of the oven when you turn down the temperature.

Let the muffins cool in their tin for 10 minutes, then remove from the tin and continue cooling on a wire rack.

If adding the optional glaze, whisk together the icing sugar and lemon juice in a small bowl. Then while the muffins are still warm, drizzle the glaze over the muffin tops. The glaze should sink into the muffins.