INGREDIENTS (Here is what you will need):
4 skinless, boneless, chicken breast halves. 
NOTE:  I have found that it is best when you buy these from the butcher counter as they will be thicker breast halves.  However, the bag halves will work just be careful when slicing them in half.

15 ounces ricotta cheese
10 ounces frozen chopped spinach thawed and drained
1 clove minced garlic (I usually substitute 1tbps of minced garlic from the jar)
2 eggs
8 ounces shredded mozzarella
16 ounces spaghetti sauce

How Hot:
Preheat oven for 350°
Lightly grease a 9×13 casserole dish (I usually use olive oil)

 
Now to out the deliciousness together:
1.  Slice the chicken breasts halves in half for the stuffing
2.  In a large/medium bowl (depending on how messy you can be…medium bowl for me … large bowl if kids are helping) mix:
          a.  Ricotta
          b.  Spinach
          c.  Garlic
          d.  Eggs
          e.  Mozzarella
Mix well

3.  Take the sliced chicken breast and spoon on mix, fold over, and place in casserole dish
4.  Cover with spaghetti sauce
5.  Bake for 45-60 minutes or until chicken is fully cooked