Might try this -

Put mixed beans, lentils, split peas and rice (super pulse mix!) into
slow cooker.
Once cooked and cooled off, put portions inside foil, then into
freezer.

To eat pulse mix portion, what should I do? Options could be -

Defrost portion or cook from frozen?
Microwave or steam portion?
How about oven cook portion?

If oven cooked, the foil wrap could be useful. Would adding a dash of
(olive) oil help?

Thanks for any advice, regards, Robert.