Start by chopping and de-seeding the peppers. Spread them out onto a baking sheet and roast for 15-20 minutes, until they are soft, and the edges are starting to char.
Meanwhile, make a quick red onion pickle. Slice a red onion as thinly as you can and add to a small bowl, squeeze over the juice of a lime and a good pinch of salt. Scrunch the onion slivers in your hand to kick-start the pickling process, leave to soften and go bright pink.
Chop your cauliflower into small florets.
If your peppers are ready at this point, you can re-use the tray to roast the cauliflower. Rub the florets with olive oil, a pinch of salt and 1 tablespoon of harissa paste; if your harissa paste is a little thick then you can use more olive oil to loosen it. If it feels easier to you, you can take a large mixing bowl and put the olive oil, salt and harissa paste in the bottom, stir to combine, and then tip in the cauliflower pieces using a spoon to mix them around and cover them.
Once evenly coated, roast the cauliflower for around 20 minutes, until the pieces are cooked through, but the edges are charred and a little crispy.
While the cauliflower is roasting, make the red pepper sauce. To a food processor, add the roasted peppers along with the rest of the dip ingredients. Blend until you have a thick consistency and season to your liking; you could add extra lemon, chilli or paprika here depending on how it tastes.
Once your cauliflower is ready, wrap your tortillas tightly in foil and warm in the oven and assemble the rest of your taco ingredients.
To serve, place all the taco ingredients on the table and layer the red pepper dip on top of a warm tortilla, followed by the harissa cauliflower, a few leaves of fresh coriander and a few pink shards of zingy pickled onion.