Soak dried porcini mushrooms in a cup of warm water to reconstitute; drain.
Lightly dust both sides of the chicken breasts flour. Sauté in 1 tablespoon oil and 1 tablespoon butter, until both sides are golden. Remove chicken from pan; reserve warm.
Add 1 tablespoon butter, portobello mushrooms and half the garlic to the pan; stirring often; cook 2 to 3 minutes. Deglaze the pan with wine; reduce. Add chicken stock and porcini mushrooms and their soaking water; boil mixture uncovered until liquid reaches a syrupy consistency.
In a separate pan, sauté spinach with 1 tablespoon olive oil, salt and pepper until just wilted. Mix pasta with tomato, 1 tablespoon butter and salt and pepper.
Place chicken breasts in the pan over the mushrooms. Add a slice of prosciutto to each breast; top with a slice of fontina cheese. Cover mixture, then simmer until cheese melts.
Place pasta and spinach on serving platter. Top with chicken breasts and mushroom sauce. Serve immediately.Makes 4 Source: