In a large bowl, whisk together the sourdough discard, olive oil, eggs, milk, water, sugar, vanilla, and salt. Mix very well.
Add the flour and whisk until smooth.
Cover the bowl with plastic wrap to sit in the fridge for 1 hour to overnight.
Set a nonstick skillet over medium heat for 1 minute to warm up.
Grease with butter, then add 1/4 cup batter per crepe. Tilt the skillet around as needed to evenly distribute the batter to a thin crepe like shape. Cook for 30 seconds to 1 minute, until set in the center, then flip to cook an additional 30 seconds. Repeat with remaining batter.