Start by making the salsa: peel and finely slice the shallots. Pop in a large bowl. Finely dice the tomatoes and add to the shallots. Halve the pepper. Scoop out the seeds and finely chop it to match the tomatoes. Add half to the bowl (keep the other half for later).
Slice the fat cheeks off both sides of the mango, as close to the stone as possible. Then slice off the thinner sides. Finely chop the flesh, discarding the skin. Add to the bowl. Grate in the lime zest and squeeze in the juice. Season with salt and pepper. Stir together to make a salsa. Set aside.
Coarsely grate the cheddar. Pop in a small pan. Add 2 tsp smoked paprika. Peel and grate in the garlic. Halve the chilli, discarding the seeds. Finely chop it and add to the pan. Chop the coriander stalks and add to the pan. Set the leaves aside.
Drain and rinse the black beans. Stir them into the cheesy mix. Add the remaining chopped pepper. Roughly chop half the spinach and add that too. Season the mix generously with salt and pepper.
Warm the cheese mix over a medium-low heat for 4-6 mins, stirring, till the cheese is melted and the spinach has wilted. Take off the heat. Put 2 tortillas on your work surface. Divide the mix between them and spread evenly. Top each with another tortilla and press down gently.
Heat your oven to its lowest setting. Warm a large, dry, non-stick frying pan over a medium heat for 2 mins. Slide 1 of the quesadillas into the pan. Fry for 2-3 mins till the quesadilla is golden brown underneath.
Carefully flip the quesadilla over with a spatula or palette knife. Or put a large plate over the top of the pan and turn over to flip the quesadilla onto the plate. Slide back into the frying pan, uncooked-side down. Cook for another 2-3 mins till golden brown underneath. Slide onto a plate and keep warm in the oven while you cook the second quesadilla.
Slice the quesadillas into quarters. Fold the coriander leaves through the mango salsa and serve with the oozy quesadillas and the remaining spinach on the side.