Combine the flour and water in a bowl and mix to a smooth dough. Turn onto a lightly floured surface and knead 3 minutes. Cover with a towel or bowl and rest 10 minutes (or at least 15 minutes if following the drier formula).

Finely chop the coriander and onion. Combine the ground meat, coriander, onion, cumin, oil and salt in a bowl and mix until even. For the chicken version, mix the thigh mince with its onion, ginger, garlic, ground spices, chilli, oil and salt.

For the achar, heat the mustard oil over medium heat; fry the garlic and ginger a few seconds until light golden, then add the fenugreek, dried chilli and Jimbu. Add the tomatoes and cook 10 minutes, stirring occasionally, until thickened. Off the heat, stir in coriander and Timur; cover and rest 10 to 15 minutes.

Divide the rested dough into 15-gram balls (about 30). Working with one at a time and keeping the rest covered, roll each to a 3-inch (7.5 cm) round on a floured surface, leaving the center slightly thicker than the rim.

Place about 2 teaspoons of filling in the center of each wrapper. Pleat and seal the edges closed so no filling is exposed.

Oil the steamer rack and arrange the momos with space between each. Bring the steamer water to a boil, then steam 8 to 10 minutes, until the wrappers turn tender and slightly translucent.

Turn off the heat and leave the lid on for 2 minutes before opening, so the wrappers do not deflate. Serve hot with the achar.