Add the vegetable stock to a saucepan and heat. While it's heating break up the saffron threads by crumbling it into the stock with your fingers. When the stock begins to simmer let it simmer for one minute and then turn the heat way down and just keep it warm while you continue with the recipe.
Add 2 Tablespoons of olive oil to a paella pan* along with the chopped onion and red bell pepper. Sauté until softened.
Add in the sliced portobello mushrooms and marinated artichokes and sauté until softened.
Add in the tomato, capers, crushed garlic, smoked paprika, sweet paprika, dried thyme and cayenne pepper and sauté for a couple of minutes.
Add the Spanish rice and the remaining tablespoon of olive oil to the pan. Stir to mix everything together so that the rice is well coated. Cook for 1 minute to lightly toast the rice, stirring it occasionally to spread the rice evenly across the pan.
Add in the prepared vegetable stock with saffron threads and the salt and pepper. Don't stir it now.
Bring the pan to a simmer and let it simmer for two minutes.
Now turn down the heat to a mild simmer for around 20 minutes until the rice is cooked. You will see the stock reducing in the pan. Keep an eye on the rice as the stock reduces.
When the stock has cooked off use a spoon to gently check to see that there is no liquid at the bottom of the pan. The rice should be soft but firm. Remove the pan from the heat.
Add the thawed frozen peas to the top of the rice, don't mix them in.
Cover the pan with foil and let the paella rest for 10 minutes.
Remove the foil and top with fresh chopped parsley and lemon wedges and serve!