Grill smoked sausages on a grill pan or outdoor grill over medium-high for 5 minutes each side and heated through. Remove to a platter and keep warm.
To prepare the grits: In a heavy bottomed saucepan, bring the chicken broth, evaporated milk and table salt to a boil.
Add the grits in a steady stream, whisking constantly, until fully combined. Adjust the temperature to low and allow grits to slowly bubble and thicken. Cook covered for 15-20 minutes until smooth and creamy. Stir periodically to prevent sticking. Add extra broth when needed to thin.
After grits have reached desired consistency stir in the half & half, butter and shredded colby-jack cheese. Stir until the cheese melts. Remove from heat, keep warm.
While grits cook, In a medium size saucepan saute the diced onion in a couple of drizzles of olive oil. Saute for 3-5 minutes until onion is soft, translucent and beginning to brown. Add the minced garlic. Saute for one minute longer.
Add fire roasted tomatoes, seasoned salt, pepper flakes, oregano, basil and sugar. Cover simmering over low heat for 10 minutes until tomatoes break down. Mix in parsley. Keep warm until serving. (Easily doubles)
To plate: Slice the grilled sausages on bias. Spread the grits onto a plate, top with sausage slices and drizzle the fire roasted tomato sauce. Garnish with additional parsley if desired. Serve immediately.