Heat up 5 cups of hot broth using the microwave or stovetop. Crush the saffron threads gently between your fingers, mix it in the hot broth, and set aside.
Heat olive oil on medium heat in a large pan. Add the sliced sausages and saute until lightly browned about 5 minutes. Remove with a slotted spoon and set aside. They'll release some flavorful oil, so leave that in the pan.
In the same pan, add diced onion and garlic with a pinch of salt and sauté until onions are translucent.
Incorporate sliced bell peppers, zucchini, asparagus, mushrooms, and beans cooking until the vegetables start to soften and reduce slightly in size, about 5 minutes. Then add the wine if using to deglaze the pan and allow it to evaporate, about 2-3 minutes.
Add the sausage back in. Stir in the rice, smoked paprika, rosemary, salt, and pepper. Allow the rice to toast slightly to enhance its flavor, about 2 minutes. If using rosemary sprigs, nestle them on top.
Turn up the burner to medium-high heat. Pour in the saffron-infused broth, ensuring it fully covers the rice. Gently press down any grains peeking out above the surface and give the pan a good shake to even out the contents. But do not stir.
It should be simmering vigorously on medium-high. Let the paella cook uncovered for about 15-18 minutes or until the rice is al dente and most liquid has been absorbed. The rice should be firm but cooked through. If some of the top rice pieces are a little firm, they will continue to soften in the next step
Turn the heat to medium and gently scatter the sliced cherry tomatoes over the pan, nudging them down just enough so they're snugly nestled and partially submerged.
hen, top the dish with peas, olives, and slivers of pimientos, and partially cover with a lid or aluminum foil. Cook for an additional 10 minutes to heat the toppings and form the socarrat.
Take a quick peek at the bottom of the pan by scooping aside a bit of rice for a glance. You're looking for a pleasant dark brown color, but not burnt. If no socarrat is in sight, up the heat for a minute or two.
Serve the vegan paella hot, with lemon wedges on the side for squeezing over the top.