Must be a midwestern colloquialism; I'm sure there some Virginian or Canadian ones I'd be stumped by. I worked in a bakery growing up, so there's double meaning for me.
Now we're cooking with gas may just be reference to self-righteous superiority of those with that variety of appliance. I didn't grow up in a house with a gas stove, and had lived 18 years of wedded bliss without one either. Electric had always been good enough. HOWEVER, the late 2005 addition to this household has pried the sty from my eye.
I use that line often these days, with the sincerest of appreciation for the DW's bounty.
I give you dollars to doughnuts that the speaker who said "dimes to doughnuts" is half of dumb and dumber.
Hmmm...from a UK website, no less. How come dollars instead of pounds sterling? I'd say the opinion is somewhat, uh, coloured.
Rather, "dimes to doughnuts" probably evolved in depression-era times to reflect the more likely coinage available (later than the Victorian era quip).