Mix cocoa and sugar together to help with later mixing and eliminate clumping; then combine first 5 ingredients in large pot, cook until thickened. (I brought it just up to rolling with almost constant stirring to prevent scorching). Add vanilla, drop in butter and stir until completely incorporated. Ladle into 1/2 pint hot jars, leaving 1 head space, add lids and rings. Place in pressure canner, vent per proper canning techniques for 10 minutes, bring up to 10# pressure (my altitude is 1300 feet), shut off heat and allow pressure to decrease naturally. Remove from canned and test for seal as usual.

This recipe was a little thin for eating prior to canning, but it worked great after. The texture is different from fresh pudding, but it is melt in your mouth smooth when eating it. Whisking smooths it out.

Mix all ingredients except for butter and vanilla.

Bring to a boil.

Add butter and vanilla, stir until incorporated.

And when you dont leave a 1? head space...you have a mess and some siphoning.