What to do with 10 lbs of prune plums my Dad brought from B.C.?
I searched the web and found a recipe for  plum sauce and plum crisp. 
Doubled the recipe for both and made a few alterations.

Plum Sauce bubbling away.

Pureed and reducing

Processed and ready for the cold room.

Oh, I charred some Anaheim Peppers to freeze and use for dinner (green chili pork burgers) too.

Crumble and plum/apple mixture.

Ready for the oven.

Baked and cooling for the deep freeze.

 Plum Sauce
1 lb prune plums halved and pitted
1 lb apricots, halved and pitted (I used 1/6 lb dried and reconstituted)
2 c cider vinegar
3/4 c water
1/4 c balsamic vinegar
1 c brown sugar
1 c white sugar
1/2 c lemon juice
1/4 c peeled and chopped ginger
1 small onion, chopped
1 hot chili, seeded and chopped or to taste.
2 garlic cloves, chopped
4 tsp coarse salt
1 tbsp toasted mustard seed
1 cinnamon stick

Combine all in large pot and simmer 1 hour. Remove cinnamon stick. Blend in small batches when cooled slightly. Be careful with a blender, and put a towel on top of the cover while holding it down. 
Return to large pot and cook it down until desired thickness. 
Pour into canning jars, tighten covers and process in boiling water bath for 10 minutes. (the recipe said to just cap, but I like to process in a water bath.)
Wait 2 weeks before using. 
I got 10 cups with a double recipe.

Prune Plum Crisp
1 1/4 c flour
1/3 c ground walnuts
1/3 c unsweetened coconut (optional, my addition because my husband loves it)
1/2 c white sugar
1/4 c packed brown sugar
1/4 tsp ground cinnamon
1/8 tsp ground cardamom
1/2 c butter, melted
2 1/4 lb prune plums, pitted and quartered (6 cups) (I substituted some apples I had for a cup or so).

Preheat oven to 375 F. In a large bowl, mix together the flour, walnuts, 1/4 c white sugar, brown sugar, cinnamon and cardamom. Slowly ad the butter and combine with a fork until the mixture is crumbly. 

In another large bowl, combine the plums and the remaining 1/4 c white sugar, toss well.  Spoon into a buttered 2-quart or shallow casserole dish. (I used 4 - 8X5 inch foil pans) Sprinkle crumbs on top, breaking up any large lumps.

Bake until the fruit is bubbling and the topping browned, 50 to 55 minutes.