Reform School Mutants

[GM Marvel]

Well, given that her description of her power's first manifestation involved a gas stove... I could justify the explosion with a simple Matter Conversion - Combustion power. And that would fit nicely with her other power being Matter Creation - Projectiles (remember picking up the plate during the cafeteria fight? I was going somewhere with that).

Create a small plate-like throwing object (or use one that is already handy), make it a timed combustible, start fires wherever you can get that projectile.

That's possible.  I don't want to discourage you but if I remember correctly, the power: Combustion kinda sorta sucks.  Sometimes MSH created powers that seemed more like regular powers but with limitations.  For example, I believe that Combustion needs time to get hotter so it's basically fire generation with the limitation that you slowly increase your damage over the turns it's used.  Where as Fire Emission just lets you use it at full power all the time.  Or you could use hard radiation which could look like flames.  Or almost any energy emission could look like flames.  (Cold Fire? Shadow Fire? ect)  As for the projectiles, there is a power called, Missile Creation that could work (Which in some cases should be just a limitation of a regular power)    Gambit's power could also be converted so instead of exploding with kinetic energy it explodes with fire.  Kind of like making the molecules speed up so fast that the object explodes in flames. 

Sorry for rambling.  I'm just finishing work and I'm tired.  This  stuff is just off the top of my head.  If it still isn't quite what you want, let me know and we can keep working on your power.