Flour

Flour is a miscellaneous item in Fallout 3 and Fallout: New Vegas.

Characteristics
In Fallout 3 it is one of the rarest non-unique items in the game. It can be used as Rock-It Launcher ammunition, however it's more important use is as an ingredient for Mississippi Quantum pie. It is not listed as a food item, but rather as a junk item. It appears to say on the front: "T.V.G. Whole Wheat Flour".

In Fallout: New Vegas flour can be used for various food recipes including fire ant fricassée and the cut recipe Ruby's Spicy Casserole.

Fallout 3
There is only one guaranteed sample of flour to be found out in the Capital Wasteland, in a diner roughly north of the Nuka-Cola plant and west of the Red Racer factory. Several vendors might sell flour, but may not have it all the time. These vendors are:
 * Gary Staley and Seagrave Holmes in Rivet City.
 * Lydia Montenegro in Tenpenny Tower.
 * Moira Brown in Megaton.
 * Knick Knack in Little Lamplight.
 * Michael Masters in Warrington Station/Tenpenny Tower.
 * Karl in Meresti station.
 * Crazy Wolfgang.

There is a small chance flour will be available for sale by other vendors and scavengers, so check their inventory on other days if it is not available.

Flour can also be found as random loot typically in schools, kitchens, grocers and mailboxes.

Sometimes flour can be found in a metal box at the Super Duper Mart.

If you have the Point Lookout add-on, flour is also sold by Panada and can be found on the ground in various places in Point Lookout such as the hotel. Haley's Hardware also has 1-2.

Fallout: New Vegas

 * Flour can be found in virtually every kitchen.
 * Two can be found in Goodsprings. One is in the gas station behind Doc Mitchell's House, and another can be found in the doctor's kitchen.
 * A large amount can also be found in Nipton houses.
 * Eight can be stolen from the Mojave Outpost Barracks.
 * Two can be found in the dumpster with no lid behind the General Store in Zion Canyon.
 * Many can be found in the Big Empty in Old World Blues.
 * There is one bag of flour near the torn-off cage door (With Patient Log Y-17 in front of the cage) in the Y-17 Medical Facility in Old World Blues.
 * Can occasionally be bought from Chet in Goodsprings.

Behind the scenes
In Vault 21, the breakfast menu states that the pancakes are made with Corn Flour and beneath that is a reference to the company that manufactured the flour, Monphanto. This is a reference to the real world company of Monsanto, an infamous multinational seed - pesticide - agriculture corporation.