Heat the butter and olive oil together in a large nonstick skillet over medium-high heat. Sprinkle the chicken on both sides with salt and pepper, then add them to the skillet. Cook until nicely browned and cooked through, about 3 minutes per side. Remove to a plate.
Add the onion and garlic to the skillet and stir until slightly softened, about 30 seconds, then add the artichokes and cook, stirring, until the artichokes are hot and the onions are translucent, 1 to 2 minutes. Pour in the wine and stir, then add the cream and more black pepper, if desired, then stir again. Let the sauce come to a simmer, then add the Parmesan and cook for a minute to thicken.
Add the pimientos, spinach and lemon juice, then stir until the spinach has wilted, for a minute or so. Nestle the chicken back into the skillet, spooning a little sauce over the top. Garnish with torn basil leaves and serve with warm bread.