Step #1 Preheat the oven to 350°F Grease 12 texas size muffin c with butter or cooking spray or line with paper muffin wrappers.
Step #2 Wash & dry the lemon.
Step #3 Cut into quarters & remove the seeds.
Step #4 Process the quartered lemon (all of it!) in a food processor/blender fitted with a metal blade for 1 min or more, until it is completely ground up.
Step #5 Scrape the lemon into a bowl.
Step #6 Without washing the food processor/blender add the walnuts & pulse 10 to 12 times.
Step #7 Add the walnuts to the processed lemon.
Step #8 Stire to mix & set aside for later use.
Step #9 Using a mixer fitted with a paddle attachment, cream the butter In a large-ish bowl on medium high speed for 1 min.
Step #10 Scrape down the sides of the bowl.
Step #11 Add the sugar & beat on medium high until light & fluffy.
Step #12 Add the eggs all at once & beat on medium speed for 1 min.
Step #13 Add the vanilla & beat for about 30 seconds.
Step #14 Mix together the dry ingredients.
Step #15 Beat one third of it into the creamed mixture just until incorporated.
Step #16 Add half the yoghurt & do the same.
Step #17 Repeat, ending with dry ingredients.
Step #18 Gently stir in the the lemon mixture.
Step #19 Spoon batter into prepared muffin tins.
Step #20 Bake for 30 to 35 mins until they are slightly browned & a toothpick inserted in the center comes out clean.
Step #21 Let cool in the pans for 5 mins, then remove to a wire rack.
Step #22 mix glaze ingredients & drizzle over the warm muffins.
Step #23 Glaze will harden in about 15 mins.
Step #24 These are at their very best served warm, but if wrapped tightly in plastic wrap once cooled, they will still taste great for up to 3 days.