I have approximately 9USD I can spend on food for the next 3 weeks

supercook.com

GO to a food bank.
Go dumpster diving.
Go to friends/family homes for dinner.
Buy milk and eat cereal.

laughed out loud

It depends, are you looking for pure sustenance or do you like want to make something fancy with your ingredients?
You could make gnocchi with the potatoes if you want. You could make a chocolate souffle with the eggs and powdered cocoa. You can make tacos with the tortillas, the tomatoes, and the beef. You could use the onions and the beef together to make a hamburger and just eat it between the sandwich bread. You can make curry rice with the spices and the rice.

>a ton of rice
Sell half a ton of rice.

At the current price, that should yield roughly $200 for meat and veg to supplement your rice meal.

indexmundi.com/commodities/?commodity=rice

If you're going for merely survival, just try to find the cheapest beans/whole chicken you can. Rice with beans and white meal it's the cheaper and the more substantial of your options.

I'm going to teach you how to cook a beef wellington, which if you make a big enough log of you can subsist on this for a good 2 months entirely.

In a food processor, liquefy the carrots, tomatoes, onions, peppers, and potatoes. In a large bowl, mix a bit of sugar, spices (I enjoy nutmeg, mustard, and pumpkin pie seasoning), the soup packets, bread, crackers, cereal, and powdered milk. Crush until uniform. Add in a few eggs (reserve at least two, you can add however many you want), and the coffee (espresso grind), and mix until it forms a dough. In another bowl, mix the beef, rice (uncooked), and tuna. Roll out the dry ingredients and eggs bowl on your counter, using half your bit of flour if too sticky, then adhere your beef. Roll this into a log, then smear on the liquefied vegetables. Cover this with tortillas until sealed, then dredge in an egg and the rest of your flower. Bake this in a 600 degree oven in an Itialian bread tray for 4 hours on low, then serve in triangle slices and garnish with tiny fingerfuls of your last egg.

For dessert, mix the papaya, honey, and cocoa powder by hand until it forms a tacky dough, then let this ferment uncovered in the center of your house overnight. In the morning ants will have accrued on the outside but died due to the sticky, nightlong froth. Re-knead making sure not to overcrush the ants. Their corpses give a lemony flavor and provide some protein. Bake this on low until it drops through your oven rack and catches on fire, then scrape out the cinder and there you have it, a tasty sweet-sour cowboy bark.

Nice

...

underrated

Cowboy food is now meme.

Get a $8.99 large pizza (Mon-Thurs only) from domino's and have one slice every three days

Buy a job

Suck some dick
Buy some McDonalds Big Mac with a side of crisp fries

5 boxes of spaghetti and 4 big cans of peeled tomatoes.
Reduce tomatoes, add any veggies you can spare of you want, some Italian seasoning and a little ketchup

excluding the grains you have, basically everything with some degree of nutrition, you have a total of 3000 calories of this

if you get a whole chicken, you can add another 2,000 calories, then you can make stock, and then grind up the FUCKING BONE and eat it, you can squeeze another 300 out of it maybe, and be left with 3-4 dollars, to get produce to supplement your nutrient intake. leaving you with 7-8k calories of good nutrition. perhaps more, if you find sales

that will leave you with perhaps 350 calories of actual nutrition per day out of 21 days. simply ration all of your food that isn't simple carbs, into 21 portions. im assuming youre an adult male, so you probably want 1800 calories a day on a ration, so 15% of your diet will be actual nutrition

this is auschwitz tier but you will survive

P.S., make sure you portion out the beef, eat that first, and then purchase the chicken a few days after the beef is all gone, so that you don't lack protein as badly for the last stretch

Watch the Martian and then plant your potatoes.