First bring a pan of water to a boil and season the water with salt. Now blanch the green peas for 1 minute. Then cool them down in ice water. After that mix the green peas with the remaining ingredients and blend this till smooth. Once it's smooth fill your desired mold. Then tap the mold a couple of times to remove any air bubbles and cook it at 140 degrees Celsius for 8 minutes or steam it at 85 degrees Celsius for 16 minutes. Then let them cool down for 5 minutes. You can already remove the flan from the mold like this, but if it's a difficult mold it might be better to freeze the flan first before unmolding it. Then let it slowly defrost for a perfect texture.
You can serve it cold, but if you want to heat it up then do this covered at 80 degrees Celsius for about 20 minutes. By doing it low and slow, you will keep the nice texture without drying out the flan.