FWIW, I tried boiling my flask directly on the stove, and it was a big mess when it came to adding the DME through the narrow opening (DME tends to clump/cake immediately when exposed to moisture, including hot steam).
The Fiesty(sic) Goat Brewery est. 2007 & Clusterfuggle Experimental Ales est. 2009
Planned: sLambic II, Flanders Red II
Primary: Fat Man Porter, Orange Blossom Mead, sLambic I
Secondary: Flanders Red I
Kegged: 3 different ciders, Janet's Brown, Barrel-aged Stout, Hallertau Blanc Pale Ale
Bottled: Flanders Red I