Add 1 3/4 cups of stock and the salt, and stir to combine. Lock the lid into place. Select Pressure Cook or Manual, and adjust the pressure to High and the time to 8 minutes. After cooking, quick release the pressure.
Unlock the lid. Test the risotto; the rice should be soft with a slightly firm center and the sauce should be creamy, but it will probably not be quite done. Add another 1/4 cup of stock and stir in the spinach. Select Sauté and adjust to Medium heat. Simmer for 2 to 3 minutes until the spinach is wilted and the sauce is creamy. If the rice is too dry, add more stock to loosen it up. Stir in the remaining 1 tablespoon of butter and the cheese. Taste and adjust the seasoning. Serve.