Pat the chicken breast cutlets dry with paper towels, then season both sides generously with salt. Measure out the rice flour into a shallow dish and set nearby for coating. Slice the lemon into thin rounds, mince the garlic, chop the parsley, and drain the capers thoroughly by rinsing them under cold water—this removes excess brine that can oversalt the dish. Have all ingredients prepped and within arm's reach before you start cooking, as the actual cooking happens quickly.

Working with one cutlet at a time, coat both sides evenly in the rice flour, shaking off any excess. Heat 2 tablespoons olive oil and 1.5 tablespoons butter in a large skillet over medium-high heat until the butter foams and just begins to brown—this takes about 1-2 minutes. Once the pan is hot, sear each chicken cutlet for about 3 minutes on the first side until golden and crispy, then flip and cook for 2 minutes on the second side. Transfer each cooked cutlet to a plate. I like to use rice flour instead of all-purpose because it creates a crispier, more delicate crust that doesn't get heavy.

In the same skillet, reduce heat to medium and add the sliced garlic along with a pinch of red pepper flakes. Sauté for about 1 minute until fragrant but not browned. Add the lemon slices to the pan and cook for 2 minutes to soften slightly and release their flavor, then remove them to a plate. Next, add the fresh spinach to the same pan and cook for about 2 minutes, stirring occasionally, until just wilted, then remove to a separate plate. These quick-cooking elements are done first so they stay fresh and don't overcook.

In the same pan over medium-high heat, add the chicken stock and lemon juice, scraping up any browned bits from the bottom of the pan with a wooden spoon—these flavorful bits are essential to the sauce. Bring the liquid to a gentle boil and let it reduce for 2-3 minutes to concentrate the flavors. The sauce should reduce by about a quarter. Add the drained capers to the pan and stir to combine.

Remove the pan from heat briefly and whisk in 4 tablespoons of cold butter (cut into small pieces), which will create a silky, luxurious sauce—this technique is called mounting the sauce. Return the seared chicken cutlets from Step 2 to the pan, nestling them into the sauce, then return to medium heat and simmer gently for 3-5 minutes until the sauce thickens slightly and coats the back of a spoon. I like using Kerrygold butter here because its rich, slightly cultured flavor elevates the finished dish.

Return the cooked spinach and lemon slices from Step 3 to the pan and gently fold them in to warm them through, about 1 minute. Divide the chicken among serving plates, spoon the piccata sauce generously over each piece, and arrange the spinach and lemon slices around the chicken. Finish with a scatter of fresh chopped parsley for color and brightness.