Chop the spinach coarsely and put into a salad bowl.
Chop the bacon coarsely .
Put into a saucepan and heat until the fat runs.
Let the bacon cook until crisp, then lift it from the fat with a slotted spoon and add to the spinach.
Discard the crusts and break the bread into pieces.
Process until just broken into small pieces but not crumbs.
Crush the garlic.
Toss the bread and garlic in the bacon fat until the pieces of bread are crisp and golden.
Put the oil, lemon juice, mustard, salt and pepper into the processor bowl and mix thoroughly .
Drain the bread pieces and garlic and add to the salad bowl.
Pour on the dressing, toss quickly and serve at once.