Melt the butter in a 6 quart pressure cooker set to the saute function. Add the onion and the roasted pepper and cook, stirring, until the onion is softened - about 4 minutes. Stir in the oregano, paprika, salt and pepper and continue cooking for about a minute.
Add the rice and stir for about a minute. Pour in the sherry and stir until it's absorbed. Add the broth and clam juice, stir.
Lock the lid on the pot and set to vent to sealing. Set the machine to cook at high pressure for 10 minutes.
Use the quick-release method to bring the pot back to normal pressure.
Remove the lid and set the pressure cooker back on saute. Add the shrimp and stir until the shrimp is cooked, about 2 minutes. Stir in the cheese. Turn off the heat and let sit for a minute or two.