When ready to cook meat, remove from marinade; pat dry with paper
towels.
Brown in a large skillet.
Place beef in slow cooker, stir
in marinade, plus celery, garlic and onion soup, cover.
Cook on Low
for 10 hours or on High for 6 hours, or until beef is tender when
pierced with a fork.

Remove beef to a heated platter and keep warm.
Turn heat control to
High.
Combine flour and 1/4 cup cold water in a cup, stir into
liquid in slow cooker until well-blended; cover; simmer 15
minutes.

Carve part of the roast into 1/4 inch thick slices.
Arrange slices
with rest of roast and Braised leeks on a large serving platter.
Add parsley potatoes and steamed whole carrots, if you wish.
Serve
gravy separately to spoon over all.

BRAISED leeks: Trim roots and about half of the green tops from 1
bunch of leeks.
Split each leek lengthwise; wash well.
Arrange
pieces, cut side down in a large skillet.
Add just enough water to
cover.
Bring to boil, cover.
Simmer 5 minutes, drain, return to
pan.
Add 3 tablespoons butter and sprinkle with 1/2 teaspoon salt
and celery salt.
Cook slowly 5 minutes longer or until leeks are
tender.
Green onions can be substituted for the leeks, use 2
bunches sliced in 3 inch pieces and cook a total of 6 minutes.