Make the quick pickles: Place the vinegar, sugar, salt, coriander, and cardamom pods into a pan and gently heat until the sugar and salt have dissolved. Remove from the heat and add the dill, radishes, and cucumber. Allow to cool.
Place a baking tray on the bottom of the oven, and pre-heat to the temperature on the instructions for the baguette. When the oven has reached temperature, fill the baking tray with boiling water and bake the baguette on the rack above. When cooked, as per the instructions, take it out and leave it to cool, covered with a tea-towel to make a softer crust.
Heat a griddle. Wipe the steak with some oil on both sides, and sprinkle with salt. Griddle the steak for a couple of minutes on either side, until cooked as you prefer, for medium rare 4 minutes a side. Take it off the griddle, and leave it to rest, loosely covered with a piece of foil.
Assemble the sandwich. Cut the baguette in half, and cut open lengthwise. Cut the steak into slices. Spread mayonnaise on the bottom half. Top with the beef, add chili, coriander, and quick pickles. Drizzle with Srirancha sauce, pop the other half of the baguette on top, and enjoy!