Put shrimp in a large bowl and cover with harissa sauce and salt and stir to combine. Set aside and let marinate for 10 minutes. When you're ready to cook the shrimp, melt the butter in a large frying pan and add in the shrimp. Cook the shrimp, stirring occasionally for 10 minutes, or until the shrimp is no longer translucent and it has turned pink.
To make the grits, in a large pot combine 3 ½ cups water and 1 teaspoon salt and bring to a boil.
In a bowl combine remaining cup of water and cornmeal and stir to combine-it will get thick.
When the water comes to a boil, whisk in the cornmeal and water mixture. Bring the mixture to a boil again and then reduce heat to low. The mixture will thicken slowly. 5 minutes after turning the heat to low, whisk in the butter and shredded parmesan cheese. This is the point when I start the shrimp. The grits should remain on low, being whisked occasionally for the next 8 minutes, then the heat can be turned off and they can rest until they are ready to be served.
To serve spoon grits into 4 bowls and top with shrimp.