I've implemented this sort of thing in the past. Without knowing your specific case, I guess that you have a parent model (ie. Pizza) and 1-n related child models (ie. Topping).
My advice is to redesign your flow to create a Pizza first then attach 1-n Topping entities to it. This would require two views and two forms.
If you want it all in one go, then write an API in REST Framework that does what I just said but via two calls from a single HTML page. You can write the HTML DOM manipulation in jQuery or ReactJS or whatever you are comfortable with. You will still end up with two calls: one to create your Pizza parent entity then subsequent calls to make Topping instances.