An uncooked meringue is a liquid foam, that you can gently fold into the other liquid ingredients of your mousse. A cooked meringue is a dry foam, that you would have to break up to mix into your mousse. Although the flavor would be good, you would definitely notice the pieces of meringue – like little bits of foam insulation – strewn throughout your mousse.

The straightforward options for you (as noted here and there at Ochef) are as follows:

There are actually lots of recipes for mousse out there that use both raw whites and raw yolks. Traditionally -a hundred-plus years ago – the yolks were ribboned with a hot sugar syrup because the sugar was too coarse to use without melting it. The use of the syrup has staged a come-back in recent years as it can bring the yolks to a temperature where potentially harmful bacteria are destroyed.