1. Peel and cut up potatoes into 1 inch pieces, Cover with water and boil until done. When done, pour into colander, drain water and then return to pot.
2. While potatoes are cooking, open cans of clams and drain, reserving juice.
3. Clean out debris from clams.
4. Cut bacon and onion into small bits.
5. Cook bacon. When bacon is ¾ cooked add onions to the pan and finish cooking. Onions should be transparent. Drain on paper towels in bowl to remove grease.
6. Add 2 cups margarine to the hot potatoes, using hand mixer or potato masher, and mash the potatoes leaving small lumps. Salt and pepper.
7. Add clams, bacon and onions.
8. Add some of the reserved clam juice to taste.
9. Add half & half a little at a time (see #10),
10. Continue alternating adding half & half and clam juice (maybe even some more margarine) until you reach the desired taste and thickness.
11. Serve hot.