The key here is good stock. You should make crab stock special for this recipe, but you could use a high-quality fish stock instead. If you don't have access to either, use good vegetable stock, or even water. One note: If you use a salty broth or stock, taste the risotto as you go, and switch to water once the dish is salty enough for you.
Pour the stock into a pot and bring to a bare simmer.
Heat the olive oil in another pot over medium-high heat for a minute or two. Add the garlic, rice and tomato paste and stir-fry them until the garlic just begins to turn golden.
Pour in the Marsala and stir vigorously. It will combine with the tomato paste to make a thick slurry, so start pouring in your crab stock. Start with 1/2 cup. Stir well to combine. Sprinkle a little salt over everything now -- unless your stock is already salty.
Stirring constantly, let the liquid evaporate. When the pot is nearly dry, add another half cup of hot stock. Keep doing this for about 20 to 25 minutes, until the rice is fully cooked but still firm.
Once the rice is cooked, add a little more stock, the parsley and the crab meat and stir to combine. Add some nice olive oil now if you want. I do. Turn the heat to low and stir until the crab is heated through. Serve at once.
This recipe also works very well with crawfish and lobster.