Preheat your oven to 220°C. Arrange the tortillas in a single layer on a lightly-oiled baking tray and drizzle over a little oil. Season with salt and black pepper. Set aside.

Halve, peel and thinly slice the shallot into half moons. Peel and grate the garlic (or use a garlic press). Halve, then remove the core from the yellow pepper and cut into 1cm wide slices. Remove the top and bottom from the courgette, cut lengthways into 1cm strips then chop into chunks. Drain the mixed beans in a colander and rinse under cold water.

Heat a splash of oil in a frying pan on medium heat. Add the shallot, pepper and courgette. Stir and cook until soft, 5-6 mins. Add the garlic and fajita spice (add less spice if you're not a fan of heat!) and stir well. Cook for 1 min more, then add the mixed beans, chopped tomatoes and Knorr vegetable stock pot. Stir well, then bubble away until the liquid has reduced by half, 10-15 mins.

Meanwhile, pop the tray of tortillas on the top shelf of your oven and bake until golden brown and crispy 3-5 mins. Keep an eye out - you want them to be golden and crispy but not burnt! Once cooked, remove from your oven and lay on some kitchen paper to absorb any excess oil.

Pick the coriander leaves from their stalks and finely chop. Finely chop the stalks (keep them separate). Grate the cheddar cheese. Halve the avocado lengthways and twist apart. Remove the stone and slip a spoon around the edge of the flesh to pop it out of its skin. Put the avocado in a bowl and add the coriander stalks and half the coriander leaves. Squeeze in some lime juice and mash with a fork.

Lay one tostada on each plate and pile high with the beanie mixture. Add some cheese and a dollop of guacamole. Finish with a sprinkling of the remaining coriander leaves. Tuck in!