In a large mixing bowl, whisk together the milk, eggs, sourdough discard, sugar, and oil until smooth and well-combined.
Add the flour and salt, then whisk until the batter is silky and lump-free.
Cover the bowl with plastic wrap and allow the batter to rest at room temperature for at least 15 minutes. This helps the bubbles to settle, which makes for sturdier crepes.
Heat a nonstick skillet over medium heat and lightly grease it with oil.
Pour in about ΒΌ cup of batter and quickly swirl the pan to coat it in a thin, even layer.
Cook the crepe for about 1 minute, or until the edges begin to lift and the bottom is golden. Flip the crepe and cook it for another 30 seconds-1 minute.
Transfer the crepe to a plate and repeat with the remaining batter, stacking the crepes as you go. Enjoy!