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I have these frozen mini pizzas which come with a silver piece of cardboard (see image at the end). I disregarded it at first, but then read the cooking instructions and it says that it is a microwave tray, which you put between the pizza and the plate.

What is the purpose of this silver cardboard tray? Does it make any difference, or would the pizza be identical without it?

enter image description here

eirikdaude
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Makonede
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    If it didn't do anything they definitely would have saved the penny or two it costs to add in cause that all adds up – eps Jun 19 '21 at 14:14
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    Could you add a picture? I never seen of those in my area – Adil Mohammed Jun 19 '21 at 15:24
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    @AdilMohammed Check out this Google Images search for "[silver cardboard](https://www.google.com/search?q=silver+cardboard&tbm=isch)". If you scroll down a bit, you'll see a bunch of round trays (often also used for cakes and the like). It's just plain cardboard with a metallic layer on one side (imagine a really thin aluminum foil on cardboard). – TooTea Jun 19 '21 at 19:42
  • @TooTea The one i had was square actually – Makonede Jun 20 '21 at 00:52

2 Answers2

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The piece of cardboard is a microwave browning element.

Ordinarily, most of the heating energy in a microwave is absorbed by water in the food. The result is similar to steaming. The material on the cardboard is designed to absorb microwave radiation and convert it into heat, attaining a higher temperature than boiling water would reach, to allow the bottom of the pizza to crisp up a little and keep it from getting soggy.

Sneftel
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    In laymen's terms, it partially converts your microwave into a localized oven, giving you slightly toasted pizza instead of a sloppy piece of bread. Do not reuse these cardboard or even with the pizza if the pizza does not completely cover the top. You will damage your microwave and/or set things on fire. – Nelson Jun 21 '21 at 08:11
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    Wikipedia says this is called a [Susceptor](https://en.wikipedia.org/wiki/Susceptor). Personally, I've mostly encountered them in sleeves for things like hot pockets. – Brian Jun 21 '21 at 13:14
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    @Nelson In the Lean Cuisine frozen pizzas, the browning element is square, the pizzas are round, and the corners of the browing elements stick out. So it's not possible for the pizza to completely cover it. – Barmar Jun 21 '21 at 13:48
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    @Barmar Hmm, the exact mechanism of these things are actually not standardized. Just pay attention to how hot things get when using it, and if it catches on fire, obviously stop and don't use it anymore. – Nelson Jun 21 '21 at 16:41
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    @Nelson Been using them for decades with no problems. – Barmar Jun 21 '21 at 16:54
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    @Nelson The rule against using metal in microwaves is a bit overstated. It's only certain metals that cause problems, but they don't trust the average user to be able to distinguish one metal from the next, so it's easiest just to say "don't put *any* metal in". Clearly, Lean Cuisine and other food producers have done the research and know which metals are okay to use, or they wouldn't be allowed to sell them that way. – Darrel Hoffman Jun 21 '21 at 20:30
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    "What's this contraption that came with my deep frozen lasagne?" -- "Oh, that's a peltier element and a magnetron which absorb heat and convert it into microwave radiation, so that the lasagne gets warm fast on the inside instead of just burning from the outside when you put it in your oven." – Peter - Reinstate Monica Jun 22 '21 at 02:01
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It makes a huge difference as it makes the pizza much crisper and allows it to cook all the way through