Preheat oven to 375°F Line a baking sheet with parchment paper. Drizzle olive oil on the parchment, then arrange the lemon slices in a single layer. Drizzle the lemons lightly with oil and season with salt and pepper. Roast for about 20 minutes, until the lemons begin to brown around the edges.
In a deep medium skillet, heat the remaining ¼ cup of oil. Season the chicken with salt and pepper and dust with the flour, shaking off the excess.
Cook the chicken over high heat, turning once, until golden, about 6 minutes.
Add olives, capers and stock and bring to a boil. Cook over high heat until stock is reduced by about two-thirds, about 5 minutes.
Add the roasted lemons, butter and parsley. Simmer just until the chicken is cooked through, about 1 minute more.
Transfer the chicken to plates and spoon the sauce on top.