Crush the Ritz crackers into a coarse crumb. Bits of larger, craggly pieces are absolutely fine (and actually add great texture), so don't worry about making the crumbs perfectly even. To do this, you can use your hands, a zip-lock bag and rolling pin, or even a food processor. Combine the Ritz crumbs on a large curved plate or tray with the cheddar, onion powder and garlic powder. Place to one side.
In a large shallow dish, whisk the egg, flour, ranch, salt and pepper until completely smooth. Place to the left of the crumb mixture.
To the left of that, place the chicken breasts on the chopping board and horizontally slice them right through the centre to create 4 even-sized cutlets. If any of them are notably uneven, just use cling film and a rolling pin to gently pound the thicker part to even them out.
Take a cutlet and coat it in the wet mix, let it hang and drip for a few seconds, then place it into the dry mix. Use your hands to coat the chicken and really press in the crumb to ensure all of the chicken is completely covered. Place to one side, then repeat with the remaining cutlets.
To Pan-Fry: add enough oil to comfortably coat the base of a large (preferably heavy-based) pan. Turn the heat to medium/medium-high. Once hot (a crumb should rapidly sizzle), carefully add the cutlets. Fry for 3-4 minutes on each side until deep golden and visibly crispy. The crumb can burn quite quickly, so be vigilant and lower the heat if you notice it browning too quickly (use tongs to peek and check). Place on a wire rack with paper towels underneath to catch excess oil. Note: you may need to work in two batches, and the safe internal temp for chicken is 165F/74C (keep in mind it'll carry on cooking a little more as it rests).
To Air-Fry: carefully place the chicken in the air fryer and generously spray the top with oil. Cook at 400F/200C for 7 minutes, then carefully flip the chicken and spray with more oil. Cook for a further 5-8 minutes, or until deep golden, crisp and cooked through the centre. All air fryers work a little differently, so if you notice it browning too quickly, just drop the heat a little. Again, you may need to work in batches.
To Bake: preheat the oven to 400F/200C. Line a large baking tray with baking/parchment paper and space out the chicken. Generously spray the top with oil and bake for 10 minutes. Carefully flip the chicken, spray with more oil and bake for a further 7-10 minutes, or until golden, crisp and cooked through the centre.
In all cases, the chicken will crisp up a little more as it cools. I like to finish with a good pinch of flaky sea salt, then tuck in and enjoy!