The night before you want to to make pancakes, mix together the sourdough discard, flour, sugar, and buttermilk in a large bowl. Cover and let rest at room temperature overnight.
In the morning, whisk together the eggs, melted butter, vanilla, lemon zest, and lemon juice. Add to the flour mixture. Add in the poppy seeds, baking soda and salt and mix until combined.
Same Day Batter
Mix together the sourdough discard, flour, sugar, and buttermilk in a large bowl. Cover and let rest for 30-60 minutes to give the flour time to hydrate.
Whisk together the eggs, melted butter, vanilla, lemon zest, and lemon juice. Add to the flour mixture. Add in the poppy seeds, baking soda and salt and mix until combined.
To Cook
Heat a lightly greased griddle or frying pan over medium high heat.
Scoop about ¼ cup of batter onto the griddle and cook until the surface has several bubbles (1-2 minutes). Then flip and cook for another 1-2 minutes. Repeat with the remaining batter.
To make the icing, mix together the powdered sugar and melted butter in a small bowl. Add in the lemon juice one tablespoon at time until a thick but pourable consistency is reached.
Notes
To keep warm, place in the oven at 200 degrees F until ready to serve.