no with just the pressure cooker. you could brown after.
How could that be? All foods are porous.
You might be able to do something interesting with fluorinert, a fairly non-toxic fluorinated hydrocarbon. Or mineral oil for that matter. But in either case I don’t think these would really allow you to do much that you can’t do with normal cooking oils.
Mercury has a very high surface tension. If you ever tried to get your hands (or anything) ‘wet’ with it, you would know what I mean.
I have; it looks like it rolls off anything. But people who handle mercury without protection do get it in their bodies.
Almost entirely through inhalation. But I agree – Mercury is a pretty toxic substance and even a minuscule amount absorbed despite the very high surface tension would be unacceptable. I’ve never seriously suggested using mercury due to its toxicity – nonetheless it would be “absorbed” by food in such small amounts as to not be culinarily relevant (I’m guessing due to my previous experience – it’s possible some foods would amalgamate with the mercury in a rather unpleasant way, so for some foods you may be right).
I’m skeptical of the idea that there could be anything that you would use which doesn’t combine with the food.
Marbles, anyone? BBs? 
(Not liquids, nor convenient, but…)
Actually, it’s quite common in some parts of the world to cook certain foods by immersing them in hot sand or salt crystals.
I went to the wikipedia page on the Maillard reactionbecause I suspected it required the presence of oxygen or air or something. I didn’t see anything about that one way or the other, but it does say that “the Maillard reaction happens noticeably around 310 °F (154 °C)” so if you want browning you have to take that into account.
Side note: I also learned that the Maillard reaction occurs “in numerous different diseases in the human body, in particular degenerative eye diseases.” :eek:
Indeed. It’s things like nuts and eggs that are cooked this way–tightly-pored foods; the sand would be larger than the pores but small enough to fit closely around the item.
Though, if you’re abandoning the liquid part, there are lots of possibilities less esoteric than hot sand.
This could be overcome with something like a fryer basket, but designed to hold the food under the surface while it cooks.
I was thinking something like molten glass would work (hey, it’s non-toxic!), but your melting point is something like 2000C, which is waaaay to hot.
This also rules out stuff like molten lava.
Then I thought molten gold would be perfect, since it’s also non-toxic. But that melts at 1000C, still way too hot.
Lead would be better at only 325C, but it’s too toxic.
So what we’re looking for is a non-toxic substance that melts below 300C.
This chart might prove helpful: The chemical elements of the periodic table sorted by melting point.
From there, it looks like molten tin might be a prospect melting at 230C. According to wikipedia, metallic tin isn’t toxic but most tin compounds are.
That’s the coolest thing I’ve seen all week.
You could try using molten gallium instead of Hg, it will melt in a hot room or in your hand (m.p. is between 80 and 90 F IIRC). It’s probably not good for you, but it’s certainly a lot safer than Hg or Pb. Don’t think it’s cheap though…
We really need a table like that which also includes alloys and compounds and organics and solutions.
A low temperature glass might work. Soda lime has a Tg of about 1000F . That’s only 200 F higher than a tandoori oven. You will need to cook fast. There may be lower melting silicon dioxide based glasses, but my google-Fu is failing me. I keep getting very toxic glasses.
If you want to live on the wild side, molten potassium is ideal.
Gravy, in a plastic/foil pouch. I realize this may violate the spirit of the OP, but I don’t think you’ll find a more efficient heat transfer method than sous-vide cooking.
I think you might be best off designing some kind of exotic convection oven. Convection ovens cook quite a bit faster than conventional ones, and they’re powered by some pretty dinky fans. Start with a wind tunnel. Replace the air with steam. Pressurize it. Heat the steam to 350* degrees. Now you’re cooking!
You could use gasses other than steam and even introduce flavorings like smoke. There’s also no upper limit to temperature. 350 is more than enough to start browning rather than ordinary steaming, and you don’t want something so hot that you burn the outside to a crisp before you cook the inside. But… you could have a super-powered broiler/grill.
I can even see the brand name now - the Pompeii 2000. The cooking speed and convenience of a pyroclastic flow in your home kitchen.
It’s not quite the Pompeii 2000, but… behold the Combi oven. 
I’ve still got a burn from brushing against one of these, five years later.
fuuuuuuuck YESSS LETS DO THIS