Ok let me make it a little simple.
1. get some spinach
2. Beef Heart
3. Some liver oil
4. "OPTIONAL" some fish growth formula "Powders" forgot the name of the brand it was just so long ago.
Ok guys, so this is the formula mostly everyone uses, not only for Betta, but for other fish as well.
U have to boil the spinach till it becomes soft and easy to blend. Yes you will blend everything together. Then you clean your Beef Hearts, take away as much fat as possible. Cut it in tiny peaces, and put it in boiling water. Do not cook it! you just have to boil it till all the "CLOUDY" stuff comes out of the meat. This will prevent your tank from getting cloudy since it already came out when boiling.
Now you proceed, and put everything in a blender or whatever u may use to get a really nice mixture. You put the spinach, beef hearts in there till you get your desire mixture. Then you need some Liver Oil and pour it over the mixture, if you got some fish growth powder that they sell at the LPS designed for discus or something like that. Add a Teaspoon into the mix. then add everything back to the blender and mix it till you get your desire mixture. Get some Zip bags for the freezer and freeze the mixture. When its frozen, its ready.
Its very simple guys. I hope my english was good enough for you guys lmao. It looks very similar to frozen brine shrimps, but its superior IMO if done correctly.