Brush any dirt off the mushrooms and shred them directly onto a baking tray by carefully digging a fork into the mushrooms at the top then pulling it towards the bottom to get uneven strands. Repeat with the spring onions.
Pick up 1/4 of the shredded spring onions and throw them into a small bowl and pour in the vinegar and 1 1/2 tbsp of the sugar. Whack the bowl into the microwave and cook on full power (800W) for 30 seconds. Leave them to cool.
Tip the mushrooms, remaining onions, oil, chipotle paste, paprika, remaining sugar and 200ml of water into a deep roasting tin. Mix well then place it under the preheated grill for 10-12 minutes, stirring every 5 minutes, until the liquid coats the mushrooms and onions in a dark, glossy glaze.
Chuck the crème fraîche into another mixing bowl. Finely grate in the garlic and the zest of a lime. Season generously with salt and stir well.
Whack the tortillas under the grill for 1-2 minutes, until deep golden in places on one side, then pull them out.
Divide the mushroom mix between tortillas, placing them on the un-toasted side. Chuck on the pickled onions, drizzle over the crème fraîche mix then rip over the coriander. Tuck in! Serves 2