M.P.
Have you considered that she may be tantruming then because she is hungry or you are rushing her? Try slowing down some during those times, giving her a bit more positive attention. Give her a snack while you cook dinner. Have her "help" you with dinner. Perhaps get her ready before you get ready or vice versa; which ever is different from your regular routine.
The tantrum indicates that she needs help controlling herself. It's best to prevent the tantrum before it gets started. Have you noticed whether or not she's hungry or tired? Are you feeling frustrated/rushed. She'll pick up on your feelings and need reassurance because she feels more vulnerable.
I, too, found that leaving the room didn't help with tantrums. What I did instead was to sit down on the floor nearby and wait until my granddaughter calmed down. I didn't say anything. Sometimes I looked at a magazine. When she stopped crying she would crawl over to me and sit in my lap. The tantrum would be over in 5 minutes or so.
A tantrum means that some need is not being met. Try to look at what's happening from her viewpoint.
Ditto what S.H. and Sandy said about feelings. Teach her how to express her feelings without a tantrum. How to say she's angry instead of spitting or hitting the dog. Perhaps give her a pillow to hit when she's upset.
I would have my grandkids run up and down the hall when I saw them beginning to getting tense and anxious. "Let's see how fast you can run to the end of the hall." "Let's jump to the sofa."
You can also redirect her attention before she reaches the point of being out of control. Change her activity. Stop and talk with her.
My nearly one yo granddaughter gets frustrated because she wants to get into the bathroom drawers when her mommy is getting ready for work. My daughter has done a couple of things. First she put things into the bottom drawer that she can get into and if that doesn't work she picks her up and sets her on the counter, giving her a comb. It's so cute. My granddaughter tries to comb her hair with this comb that's as long as her arm.
Find ways to validate her feelings and then redirect her attention.