In a small skillet or saucepan, combine the butter or ghee with the chopped tomato, minced garlic, bay leaf, cajun seasoning, and 1/2 tsp salt.
Cook this mixture over medium high heat for 5-8 minutes, until the tomato has softened and the garlic and spices are fragrant.
Place the salmon on a piece of aluminum foil on top of a rimmed half sheet pan, and crimp the edges of the foil up slightly.
Spoon all of the tomato Cajun oil over the salmon, spreading it evenly over the top. If you are someone who likes your food well-seasoned, you may optionally sprinkle a touch more salt over the top of the salmon.
Bake for 14-16 minutes, until the fish registers between 125-140F, depending on desired doneness. 125F is for medium and what I recommend, and 140F is for fully done salmon. This is assuming about a 1" thick piece of salmon. You may need less time if doing smaller or thinner pieces, and you may need more time if you have a thicker piece. Go by doneness using a thermometer.
Serve the salmon by pouring the oil over the top. I like to use a basting brush to spread it evenly. If desired, sprinkle a few fresh thyme leaves on top for garnish. Enjoy!
Note on calories: this assumes you lick up every last drop of oil, which I find I usually have some leftover after I've finished eating. As always, take calories as an estimate.*To deseed the tomato, slice it in half through the middle (not through the stem, but through the widest part of the tomato), then use your finger to poke out all the seeds and juices by pressing into the crevices.**If you're using wild salmon, you may need to reduce cooking time because it's leaner and usually thinner. I prefer to use a good quality Atlantic farmed salmon, but if you're going to use wild, I recommend something like a King salmon over sockeye.