Aloo Posto Recipe: Poppy Seed Paste Without the Grit

Aloo posto looks like nothing: potato cubes in a pale, creamy coat. It is also one of the easiest dishes to get wrong, because the whole thing rests on a poppy seed paste. Grind it badly and you have sandy potatoes. This aloo posto recipe walks through the paste first, since that is where the dish is won.

Our aloo posto recipe serves 4 and takes 20 minutes to prep and 20 to cook. The ingredient list is short: 4 potatoes, cubed; 4 green chillies (2 for the paste, 2 slit); 4 tbsp mustard oil; 1/2 tsp nigella seeds; 1/2 tsp turmeric; 1 tsp salt; and poppy seeds, which the method soaks in warm water.

What to buy

Bengali cooking uses white poppy seeds, called posto. They are cream coloured, and smaller and milder than the blue-black seeds sold for baking in many supermarkets. Blue poppy seeds work in a pinch but give a grey, slightly bitter paste.

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Look in South Asian and Bangladeshi grocers, usually in 100 g bags. Rules on poppy seeds differ by country, and some places restrict how they can be imported or sold. Check local guidance before you order online.

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The recipe data does not state a seed weight, so use about 3 to 4 tbsp (30 to 40 g) for 4 potatoes as a starting point and adjust to taste.

The grind: soak first

The method says to soak the seeds in warm water for 20 minutes, then grind with 2 green chillies into a smooth paste. The soak softens the seeds so the blades can break them.

1. Cover the seeds with warm water, not boiling. 20 minutes.
2. Drain, keeping a spoon or two of the water.
3. Blend with the 2 chillies and a pinch of the salt, adding the soak water a teaspoon at a time.
4. Stop when you can no longer feel grit between your fingers.

A mortar is the traditional tool, but a small blender jar works if you keep the seeds wet. A dry grinder pulverises them to dust that clumps. If your paste is gritty even after blending, rub a little between thumb and finger. If you feel grains, blend another minute with a spoon more water. Our guide to grinder, mortar and blender explains which jar for which job.

Cooking it in five steps

1. Heat the mustard oil, then add the nigella seeds and let them sizzle for a few seconds.
2. Add the cubed potato, turmeric and salt. Fry for 5 minutes, turning, so the edges colour lightly.
3. Add the poppy paste and the 2 slit chillies. Mix well.
4. Pour in 1/2 cup (120 ml) water, cover, and simmer on low about 12 minutes, until the potatoes are tender.
5. Serve with steamed rice and a wedge of lemon.

The recipe insists on mustard oil, not just any oil, because its sharp aroma is what lifts the mild paste. See our mustard oil guide if the raw smell puts you off, and how to heat it.

Why it goes wrong

• Gritty texture. Seeds were not soaked, or the blender was dry. Soak and add water.
• Bitter taste. Blue seeds, old seeds, or the paste scorched in a too-hot pan. Keep the heat low after the paste goes in.
• Pasty, glued potatoes. Too little water or the lid stayed off. Add a splash and cover.
• Bland. Under-salted, or no green chilli. The chilli is part of the flavour here, not decoration.

Old poppy seeds can taste musty. Smell them before you soak: they should smell faintly nutty.

Small choices that change the dish

Cut the potatoes into 2 cm cubes so they cook in the 12 minute simmer. Larger pieces stay firm in the middle while the paste thickens, and you end up adding more water than the recipe allows. Do not peel too thickly; thin peeling keeps the potato from dissolving into the paste. Some cooks leave the skins on baby potatoes, which holds the shape well.

Keep the chillies. The 2 slit ones are not there for heat alone. They perfume the gravy as it simmers, and you can lift them out at the table if the heat worries you. A final squeeze of lemon, as the recipe suggests, brightens the mild, nutty paste.

Making it a meal

Aloo posto is a side dish in Bengali meals, eaten with rice and dal. A simple weekday plate would be posto, musurir dal (red lentils) and a fried fish or a thin macher jhol. Posto is also made with ridge gourd, zucchini and green beans. Zucchini cooks in about 8 minutes, so add it after the paste.

Shopping list for one posto dinner

• 500 g potatoes (about 4)
• 30 to 40 g white poppy seeds
• Green chillies
• Mustard oil (small bottle)
• Nigella seeds
• A lemon

Store leftover poppy seeds in a sealed jar in the freezer, since their high oil content can turn them rancid in a warm cupboard. <!-- VERIFY: freezer storage advice for poppy seeds; commonly recommended, source not checked -->

If you want to know whether the rest of your pantry works for this dinner, Degchi can check the list.