Cut the onion into slices with a thickness of 0.75 cm across and break them down into rings.
Combine all the ingredients except the water into tempura mix.
Add the water gradually, stirring with a fork or whisk until you get a thick and not very liquid texture.
Heat oil for deep frying.
Dip each ring in the batter and take out and make sure she was covered on all sides with oil and place immediately in the oil.
Put each time 5 - 6 rings. Fry until golden and remove to paper towels.
Continue this process until everything is ready.
It really is as easy as that!
Enjoy!
Serve with ketchup, chili or any other dip