Make the dough: Place flours and salt on a butcher block or large plate and create a mound with tall walls and a large well in the center. Add eggs and sourdough discard in the center of the well.
120 grams all-purpose or 00 flour, 40 grams semolina flour, 6 grams salt, 2 egg, 75 grams sourdough discard
Using a fork, break the egg yolks and stir in the sourdough discard. While keeping the walls intact, begin incorporating the flour into the egg and discard paste until a majority of the flour has been mixed in.
Work mixture until all dry bits of flour have been hydrated. This may take a while, but don't worry the ingredients will be integrated eventually. Knead the dough until smooth.
If your dough feels too wet and slack, add up to 30 grams (¼ cup) of all-purpose flour, a little bit at a time.
Allow the dough to rest: Wrap the dough in plastic and allow it to ferment at room temperature (75 F / 23 C) for at least 2 hours before using.
Ferment dough (optional): After 2 hours, place in the refrigerator for at least 2 hours or up to 48 hours to ferment. Rest time is essential for pasta, this allows the flour to hydrate fully and gluten to develop so it doesn't break apart as it cooks.
Laminate the dough (optional): Liberally dust the dough with flour. Using a rolling pin, flatten the dough into a long rectangle, about 4 inches wide. Brush off any excess flour. Grabbing the short side, fold the dough in thirds to laminate it, this strengthens the gluten further. Roll it out to a thickness that will fit into your pasta machine (if using). Then run it through the rollers to help the dough adhere to itself. If you don't have a pasta machine, simply use your rolling pin to roll out the dough. Cut the pasta: Cut the pasta by hand or by using a machine (see step-by-step instructions in post).
Cook the pasta: Bring a large pot of salted water to a boil. Drop the pasta into the water while gently separating the strands. Cook the pasta for 60 to 90 seconds, this pasta cooks very quickly so make sure you watch for doneness.
Serve and enjoy: Drain the pasta, toss with a little olive oil to prevent from sticking and serve with the sauce of your choice.