I use homemade shrimp stock here, but other stocks and even chicken stock will do in a pinch. Similarly, while I prefer shrimp I've caught myself, any decent shrimp will do; I recommend Gulf or boreal shrimp.
Heat the first 2 tablespoons of butter in a medium pot over medium-high heat. Add the shallot and rice and saute, stirring often, until both are translucent, about 4 to 6 minutes. Add the garlic and cook another minute.
Pour in the white wine and stir it in. Risotto hinges on nearly constant stirring, so you will need to be at the stove for a bit. Turn on some of your favorite music. When the wine has been absorbed, add 2 ladles worth of the shrimp stock. Stir it in and add the saffron.
Stirring frequently, if not constantly, let the rice absorb the stock. The stirring sloughs off the starches from the rice and makes a creamier risotto. When that stock is nearly gone, but before the rice begins to stick to the pot, add another ladle and continue. Keep doing this until the rice is al dente -- tender, but not mushy. It'll take a solid 20 to 25 minutes.
Stir in the shrimp, peas and parsley, along with another ladle of stock. Let this cook until the shrimp are cooked through, about 3 to 5 minutes. Turn off the heat and add, little by little, more stock or water to make the risotto loose, like a porridge. Stir in the butter, then some black pepper. Serve at once.
NOTE: You must use one of the four varieties of rice I mention in the ingredients or the risotto will not work. Arborio is by far the most common, but if you can find it, Vialone Nano is my favorite for seafood.