In a large pan, sweat onions in butter until translucent. Add garlic and rice, stir well.
Add half of the wine, stirring until wine is almost completely absorbed by the rice. Repeat.
Add stock, about ½ cup at a time, stirring constantly. As rice absorbs one ladle of stock, add another and continue stirring.
Once rice is almost cooked stir in as much of the lemon zest as you want (we like it really lemony, and use all of it), and season with salt and pepper to taste. Add scallops and shrimp along with one final scoop of simmering stock. Stir gently until seafood is cooked through. Remove from heat.
Stir in parmesan cheese and parsley, just until well incorporated and smooth. Serve hot, garnished with more parsley and parmesan.