The easy way!
Canned marrowfat peas (they have allready been soaked & sesoned etc)
Butter
Salt, pepper, cream or other seasoning optional
1 drain peas
2 mash peas, with a fork, masher or blender (pulse mode).
3 add a little putter to the pan with the peas
You can also do the same with frozen peas after boiling them!
4 stir & simmer till warm