Bring 1 cup of water to a boil in a small saucepan.
Whisk in the stone-ground grits, reduce heat to low, cover, and simmer for 15-20 minutes until tender.
Stir the non-fat Greek yogurt, sea salt, and black pepper into the cooked grits until creamy and smooth.
While grits are simmering, heat olive oil in a large skillet over medium-high heat.
Add the diced bell pepper, yellow onion, and celery to the skillet, sautéing for 5 minutes until softened.
Add the minced garlic and shrimp to the skillet, then sprinkle with the Cajun seasoning.
Cook the shrimp for 2-3 minutes per side until they are pink and opaque.
Spoon the creamy grits into a bowl, top with the shrimp and vegetable mixture, and garnish with sliced green onions.