Original recipe by MARLANA ADAMEK on AllRecipes; incorporating tweaks recommended by naples34102, and me. Amounts for butter, olive oil, salt, pepper, and paprika are my best estimates. Adjust as needed and/or to suit your personal tastes. —June
Heat olive oil in skillet over medium heat. Lower heat to medium-low. Add garlic and spinach. Saute until spinach is wilted, tossing as needed to cook evenly. Cook in batches, if needed. Set aside (on plate or in bowl large enough to hold the spinach, mushrooms/onions, and chicken) and keep warm.
Melt butter in same skillet. Add onions and mushrooms. Saute over medium-low heat until onions are soft and translucent. (Start prepping chicken while onions and mushrooms cook.) Remove from skillet and keep warm.
Dredge chicken in flour, shaking to remove excess. Add olive oil to skillet as needed. Cook chicken over medium heat, turning once. Remove from skillet and keep warm.
Add broth and wine to the skillet, stirring to incorporate the yummy brown bits on the bottom of the skillet.. (I just happened to have cubes of homemade chicken broth in the freezer, cooked down to concentrated form. Use prepared broth or water if homemade broth is not available.) Bring to a low boil, reduce heat, if needed, to maintain simmer. Simmer until reduced by half. Add the remaining butter, stirring until melted.
To serve, put spinach on a platter or on each plate. Put the chicken on top of the spinach, top with onions and mushrooms, drizzle with the pan sauce. (I ate this with a baked potato, also drizzled with the pan sauce. Pasta or rice or an additional veggie would also work.)