Given a paragraph about cooking, and a set of conversational question answers about the paragraph, generate a relevant question to the topic of the paragraph. The paragraph has the prefix 'CONTEXT:'. Each conversation question has a prefix `Q:` followed by the answer prefix `A:`.

[Q]: CONTEXT: The primary reason is definitely convenience. If you don't want skin and seeds in your sauce, then you have to do some work to avoid it. Yes, it's possible, e.g. passing through a food mill, or blanching and peeling plus retaining only the flesh, but having it already done is a whole lot easier.Passata is usually much thicker too, so it won't need as long a cooking time to reduce into a non-watery sauce as fresh tomatoes. On top of that, you don't have to worry about whether you can find good fresh tomatoes, e.g. if it's winter and they're out of season.Your two cases for comparison seem to overlook this: if you just chop and cook, you'll have skin and seeds in your sauce, as well as excess liquid to cook down, while if you use passata, you won't. (Also, for what it's worth, you'd need pretty giant tomatoes to get the equivalent of 3/4 cup of passata out of one tomato.)Of course, if you don't mind skin and seeds, it's also perfectly fine to simply cook fresh tomatoes and be done with it.Note that you can often get similar advantages from other canned tomato products. In the US, crushed tomatoes are far more common, and a roughly similar texture. (Peeled whole tomatoes, diced tomatoes, tomato sauce, and tomato paste can also be useful depending on what texture you're aiming for.)  <sep>  Q: What exactly is Passata? A: crushed tomatoes  Q: Is it better to use Passata instead of fresh tomatoes? A: The primary reason is definitely convenience 
[A]: Is the procedure that much more difficult to use fresh tomatoes instead of using Passata?


[Q]: CONTEXT: Transfer of heat. First you need a hot pan (sprinkle some drops of water on the pan, it should sizzle). Then you add a drop of oil and swirl it around. When the oil forms a striated pattern, it's hot. Then you put the meat in.The hot oil helps to transfer heat from the bottom of the pan to the meat. You only need a spoonful of oil.  <sep>  Q: Why do people put oil/butter in pan when frying ground beef? A: Transfer of heat. First you need a hot pan  Q: But doesn't the fat from the beef do that? A: The hot oil helps to transfer heat from the bottom of the pan to the meat. You only need a spoonful of oil  Q: oh I see, how much butter would you need? A: you add a drop of oil and swirl it around 
[A]: So would it be like a tablespoon of butter if you didn't want to use oil?


[Q]: CONTEXT: I've never tried steaming bok choy, but yes, the ribs and leafy bits cook at different speeds.For stir frys I trim the bottom so the ribs come free, clean off any dirt that's gotten trapped in between, then stack up the leaves and cut the leaves from the ribs. I slice the ribs into about 5mm / 3/16" slices, and add them towards the end; the leaves I cut into ribbons (perpendicular to the ribs), and stir them in at the last second, so they barely cook. The center I just chop the top off the leafy bit, and slice the more rib-like bits a litte larger than the rest of the ribs (they're thinner, so cook faster).As I've never tried steaming it, and I don't tend to cook in bags (except for silver turtles when camping), this is going to be a complete guess. Now, it tastes fine al dente, so you could leave the ribs as large as I use for a stir fry, but en papillote tends to be fancier cooking, so I'd probably try for maybe 1/6" slices or a little thicker (maybe 2-3mm), and if you had a mandoline so they all came out even, that'd be great. I'd still cut the leaves into ribbons, just because it's easier to eat than a huge intact leaf.I'd assume that the leaves would cook at a similar rate as spinich, and the ribs closer to fennel, if that helps at all.  <sep>  Q: How should I prepare Bok Choy before I cook it? A: trim the bottom so the ribs come free, clean off any dirt that's gotten trapped in between, then stack up the leaves and cut the leaves from the ribs 
[A]:
Should I separate the white stem from the leaf and eat both?


