Over an open flame or in the broiler, roast your bell peppers until the skin turns black. Remove from heat, peel and julienne.
In a large saute pan over medium heat, add olive oil and chopped onions. Cook for about 10 minutes or until your onions are clear and have a slight golden colour.
Split your chicken breasts and coat generously with smoked paprika, dried basil, salt and pepper. Add to saute pan and sear on both sides for about 5 minutes or until browned.
Add roasted bell peppers, white wine and garlic. Reduce heat to low and cover. Cook for about 15 minutes.
Once the chicken has cooked through and is tender, remove your chicken from the sauce and place in a bowl. Add butter to the saute pan and continue cooking the remaining sauce in the for another 15 minutes on medium heat until it has reduced by half.
Chiffonade your spinach and add to the pan along with the chicken in the reduced sauce for about 3 minutes on low. Add salt to taste and serve alone or over pasta.