Potted Pork Tenderloin with sweet Onions and Apple

2 pork tenderloins, smartly-trimmed and cut into significant chunks (about 2 1/2 pounds)

1 1/2 teaspoons ground fennel or fennel pollen

Kosher salt and freshly ground black pepper

Flour, for dredging

2 to three tablespoons added-virgin olive oil

three tablespoons butter

four medium onions, cut into skinny wedges, root end connected

2 medium Macintosh apples, peeled and chopped

2 sparkling bay leaves

a few sprigs fresh sage, very thinly sliced

1/4 cup calvados

1 cup chook stock or cloudy apple cider