How to Make It
Lightly pound the chicken breasts 1/2 inch thick. Season with salt and pepper and dust with the flour. Heat 2 tablespoons of the olive oil in a very large skillet until shimmering. Add the chicken and sauté over moderately high heat until cooked through, 8 minutes. Transfer to a platter, cover and keep warm.
Wipe out the skillet. Add the spinach in batches and cook over moderately high heat, tossing, until wilted; transfer to a colander. Press to remove the liquid.
Wipe out the skillet; add the remaining 1 tablespoon of olive oil. Add the leek and garlic and cook over moderately high heat until softened, 2 minutes. Add the spinach, parsley and tarragon and toss. Add the lemon juice and currants; season with salt and pepper. Spread the spinach on plates, arrange the chicken on top and serve.