If using baby spinach, place spinach in a large bowl and pour over boiling water until all is submerged, pushing leaves down as needed. Leave for a minute then drain and allow to drain as it cools. If using larger leaf spinach, put the spinach in a pan of boiling water and boil for about 2-4minutes, until wilted and soft then drain.
Once the spinach is cool, squeeze well and squeeze again to get as much moisture out as possible. Roughly chop if larger leaf, then put in a food processor with the eggs, egg yolk and salt and pulse until well chopped and mixed, scraping down as needed.
Add the flours about ½ cup at a time and pulse three or four times after each addition. Add the olive oil part way through. Once all added, pulse until the dough comes together, away from the sides into a ball.
Remove the dough to a floured surface and knead with floured hands for about 5 minutes. It should be soft but not sticky - if it is, add a little more all-purpose/plain flour as you knead.
Wrap in plastic/cling film and allow to rest at room temperature for around 30min. At this stage, you can keep the dough in the fridge for a day or two until ready to use.
When ready, divide the dough into 4-6 sections and cover the pieces you aren't working with with a damp cloth to save them drying out. Prepare some trays by dusting them with semolina flour.
As you work with each piece, flatten it out slightly, dust with flour then put it through your pasta roller on the widest settings a few times (3-5 about right) until smooth, dusting with flour in between if at all sticky. Then move up the settings rolling once or twice at each settings until you get to the thickness you would like. Then either use the cutter attachment or hand cut and place the ribbons onto the prepared trays in a single layer and cover with a cloth (damp if they'll be left any length of time).
Once all is done and ready to cook, place handfuls at a time in boiling water for around 2-3 minutes.
Serve with your preferred sauce/addition eg browned butter, mascapone, pesto, roast tomato sauce.