For a blackout, the things you should stock up on are essential and non perishable foods like peanut butter, canned foods, protein bars etc.
You should also stock up on at least 1 gallon or more of water per person per day as well as flashlights with extra batteries along with a manual can opener, battery powered radio, and chargers for phones.
Keep cash on hand and also focus on food items that don't require any cooking or refrigeration.
If you do need to cook during a power outage you could cook on an outdoor grill outside or use a propane stove if you have one.
Having a solar powered battery bank or solar generator as they are called is also a good idea and even an ice chest if needed to keep foods cold with ice.
Water is very essential to life and you should have at minimum of 1 gallon of water per day for drinking per person and more is better.
If you have city water, then you should maintain water supply through the city water supply as long as the water towers are kept full.
If you're on a well, then you will need power to power the well pump and so it's best to stock up on water including water for flushing the toilet in the event of a power outage.
Canned foods like canned tuna, canned chicken, canned salmon, canned beans, canned soups, canned fruits and canned vegetables are great to have and they can also be eaten straight from the can.
Pop top lids are best, but as long as you have a manual can opener the regular canned goods can also work well during blackouts.
Ready to eat foods like crackers, protein bars, dried fruit, trail mix, nuts and peanut butter are great to eat during blackouts.
Peanut butter and some bread can make a nice filling peanut butter sandwich and even adding peanut butter to some crackers.
And even some ready made peanut butter crackers or other crackers or even snack cakes and cookies are good to eat during a blackout.
Breads, cereals and dry snacks as well as canned milk is good to have on hand during blackouts.
Having LED flashlights, lanterns, handlamps and even an extra external battery for your phone to keep it going when the power is out and you have no good way of charging your phone.
Even a battery powered or hand crank weather radio is good to have.
For heat, if you have a wood stove, then stocking up on plenty of firewood is a good idea or if you have propane heat, then making sure you have propane to get you through the blackout is recommended.
Having a portable generator and the gasoline to power it is also a good idea if you can do so.
Using a portable generator even part time is good to keep your lights on and refrigerator going and make the blackout more bearable.
Or if you can have a whole house natural gas or propane generator installed, those can be well worth the money and when maintained properly they will automatically start up when the power goes out and then turn back off when the power comes back on.