To make the garam masala, place all the ingredients except the nutmeg in a spice or coffee grinder and blitz for 30–40 seconds to a fine powder, then mix in the nutmeg.
Heat a wok over medium-high heat, then add 2 tbsp of oil. Once it’s shimmering, add the onion, lemongrass and garlic and stir-fry until the onion turns translucent.
Meanwhile, mix the curry powder, chilli, turmeric and 1 tsp garam masala with enough water to make a paste. Add to the wok and cook for 2–3 minutes, stirring constantly.
Add the meat and cook, stirring now and then, until it is well coloured and the moisture has evaporated. Season to taste with salt and pepper, and add enough water to cover the meat.
Bring to the boil, then reduce to a simmer and cook until all the liquid is absorbed. Leave to cool.
Beat the eggs in a large bowl, then add the cooled meat mixture and stir to combine.
Cut each piece of baguette in two lengthways (but not all the way through) and open them up.
Generously grease a large non-stick frying pan with the remaining oil, heat over medium-high heat, then add a large dollop of the omelette mixture and cook for 1–2 minutes, stirring and tossing until softly set.
Open out a cut baguette and place it on top of the omelette in the pan, crust-side up, pressing gently so the omelette sticks to it.
Cook until the omelette is firm, brushing some butter on top of the baguette as it sets.
Remove the baguette and omelette with a spatula and fold together to form a sandwich.
Top with coriander and serve with a mix of some chilli sauce and tomato sauce, to your taste.
