Beetroot and leeks in raisin sauce

SOURCE This recipe is from De Re Coquinaria, a compilation of Roman and classical Greek cookery. It is attributed to Apicius, who was believed to be a great epicure but about whom very little is really known.
The recipes have been adapted for the modern kitchen by J. Edwards in The Roman Cookery of Apicius (Random House, 1984). We have made some of the recipe steps more explicit for the novice cook.
Serves 2–3 as main course, 4 as side serving
Time (approx): preparation 20m cooking 25m

600g beetroot*
3 or 4 leeks
40g raisins
1 tsp ground coriander
1/4 tsp ground cumin
2 tsp Seven Acres vegetable stock concentrate**
15ml olive oil or vegetable oil
15ml white vinegar
Salt and pepper to taste
1 tbsp flour (approx.)
* prepared weight.
** Or use 1 tsp of good-quality bouillon powder or a stock cube.
Knife with a sharp blade
Plastic or wooden spoon or spatula for stirring
Vegetable peeler
Large saucepan
Measuring jug of at least 500ml capacity.
A hob or other direct heat source for cooking; Space to chop.
Advance preparation
None required.
Preparing the Vegetables
Peel the beetroot (beetroot juice stains everything so either wear rubber gloves or wash your hands now and then during the process).
Cut larger beets into halves or quarters if necessary—the separate beets/pieces should be roughly equal in size.
Slice the white part of the leeks.
Cooking the meal
Boil enough water to get 500ml; put the stock concentrate in a jug or bowl, add 500ml hot water and mix.
Put the stock in the saucepan and add the raisins, coriander and cumin. Bring the mixture to the boil, and then add the sliced leeks and the beets.
Turn down the heat and simmer for about 25 minutes, or until the vegetables are tender.
Thicken the stock with a small amount of flour, 1 tablespoon should be enough.
Serve the vegetables. Before eating, shake the jar containing the oil and vinegar to mix them, then sprinkle this over the vegetables.
Suggested accompaniment
If eating as a main meal, try some lightly steamed green vegetables or greens to set off the richer, fruitier flavours of the beetroot and raisins.