Rinse and scrub the clams. Discard any clams with broken shells. Purge the clams of sand by covering the clams in a large bowl with salt water. (You want the taste of the water to be similar to seawater.) Allow the clams to purge for about an hour. Drain the clams, being careful not to pour the grit back over the clams.  

In a large heavy pot, heat 2 tablespoons of olive oil and add in the clams. Cover tightly and shake the pan until the clams start to open. As they open, remove the clams to a bowl.  Discard any clams that have not opened. Turn off the heat. Strain the liquid produced from the clams – use either cheesecloth to strain or very carefully pour off the liquid leaving the sand behind.  Add the saffron to the liquid and allow to bloom while you prepare the rest of the dish. Set the clams and the liquid aside.

Heat the remaining 1/4 cup olive oil in the same large heavy pot. Add the minced garlic and cook over moderately high heat for approximately 30 seconds.  Add the white wine and simmer for few minutes. Add in the diced tomatoes and a pinch of hot pepper flakes.  Bring to a boil then reduce to a simmer and cook until the tomatoes soften (abut 10 minutes).  Add in the reserved clam juice and parsley and simmer for approximately 5 minutes.  Taste the broth and adjust seasonings.  (As clams are usually very salty, I find I typically only need to add pepper.)

Add in the stock and 2 cups of water. Bring to a boil and add in the fregola. Cover and reduce heat to a simmer. Cook, stirring occasionally, until the fregola is tender to the bite (about 15 minutes). If the mixture becomes too thick, add more water to thin.

Put the clams back into the wonderful broth to reheat for a few minutes and then you are ready to serve! Sprinkle with additional chopped parsley and serve immediately with freshly warmed toasted bread.