I’ve looked up high altitude cooking and most of the substitutions are in baking (cookies, muffins) and in breads.
When I parboiled potatoes they took quite a while to come to a boil and cook. We had a leaky tea kettle here so I put it up in the cupboard and bought us an inexpensive electric pot that boils water for tea in 1/4 the time as it takes on a high-powered gas stove!
So when I went to make corn on the cob (two ears for $1.00) I tried a trick. I husked the corn, measured the water I’d need to cover in the pan and placed that water in the electric kettle. It came to a full boil and the machine shut off. I immediately poured the water over the corn and lit the burner and it took nearly five minutes to bring the water back up to a boil (the corn, two ears, was at room temperature).
After that, I left the corn on a rolling boil for ten minutes and then let it sit in the water while I put dinner out. It was very crunchy. Not tender-sweet crunchy but barely nearing cooked crunchy.
We’re at 7,500 feet above sea level and I haven’t yet checked at what temp water boils around here. Probably 150-160 degrees. Any ideas? Chime in Chowhounds and Leftover Queen! Thanks, Dee
Cooking with Dee 
I’ve done 99.9% of my cooking within 75 miles of the Red River and east of Lake Texhoma so I can’t help you there but I do know my mother said it took a pressure cooker to cook pinto beans in New Mexico. Seems like overkill for corn on the cob doesn’t it? When my granny in Belen, NM showed me how to make a pie back in the early 60’s I don’t remember any issues with cooking it. I do have her cook booklet, “Cocinas de New Mexico fromthe electric company. It gives the following instructions:
“First, we’re living in a high dry climate, one mile or more above the sea: so foods boil quicker but need to cook longer. The dry air can play tricks on you. Remember to seal everything moist of course; but, also remember that when cooking by direct heat (broiling) you’ll need to adjust the food a bit farther away than you do in a moist climate to assure the same degree of doneness. Also, your favorite cake recipes will probably need some adjusting.”
Here is more:
Water boils at 202 degrees at 5000 feet and 198 degrees at 7000 feet meaning that you will need to cook everything longer. This is because the food is cooking at a lower temperature.
Cook candies to a lower temperature than stated in sea level recipes to coompensate for faster evaporation. The rule is lower the temperature one degreee for each 500 feet of altitude. We recommend that you do not use the candy thermometer alone, as cold water tests are more accurate and should be done even if a thermometer is used.
Deepfat Frying:Lower the temperature about 2 to 3 degrees for each 1000 feet of altitude or about 10-15 degrees for 5000 feet and 14-21 degrees for 7000 feet.
Canning: Increase the processing time for the water bath method one minute for each 1000 feet elevation if the processing time is 20 minutes or less. Increase the processing timme 2 minutes for each 1000 feet above sea level if the processing time is more than 20 minutes.
For pressure canning, increase the gauge pressure ordinarily used one pound for each 2000 feet above sea level.
Good Luck!
Dee I wonder if the microwave wouldn’t do a more consistent job for steaming/parboiling vegetables??
— another flatlander