The philosopher's diet, as attested by sources throughout history, consists of roast meats, eggs, roots and fruits, and milk products, prepared simply. It furthermore consists in not eating too much. This is approximately the diet that Plato sets for his guardians, and often promoted by actually existing spartanoid regimes.
The Spartans had their famous "black soup" (melas zomos), a broth made from meat, blood, salt, and vinegar. It was the common meal of the citizen class that they ate in their collective dinner clubs. The Germans at one point also promoted the "one pot meal" of meat and vegetables cooked into a soup that is still popular today. The english tradition of roast beef, beef stew, and black pudding comes close as well. Plato attempts to dispense with the pot, but we can take this to be similar to his attempts to dispense with marriage. Is the one pot meal of black soup the one true meal?
It is very easy to make. Just put a big block of meat in the pot with butter and salt, brown it a bit if you like, then pour in the root vegetables, vinegar, and water and either boil or bake for a few hours. Bones and blood would be a good addition. Tender, nutritious, austere.
We may have to start a black soup dinner club on the old spartan model. Everyone pitches in with offerings for the meat etc, we throw it all in one big pot, cook it up, and discuss the week's readings. Who would be into this?
The addition of blood to the soup base in melas zomos reminded me of the French ritualistic meal of eating ortolan buntings. The birds are trapped in dark cages, forced to gorge on figs and grain, and then once they have doubled in size, drowned in a bath of armagnac, and finally plucked and roasted. The kicker is that they are eaten whole, except for the feet and beak — bones, organs, everything. Diners must cover their heads with a napkin to hide their cruelty and gluttony from God.