Pat the salmon cubes dry with a paper towel so they sear instead of steam in the pan. Toss them in a bowl with Cajun seasoning, smoked paprika, garlic powder, salt, and pepper until every piece is evenly coated. Heat two tablespoons of butter in a large skillet over medium-high heat and sear the salmon bites for about two minutes per side until golden.
Once the salmon is nearly cooked through, lower the heat and add the remaining butter along with the honey and minced garlic straight into the skillet. Let it bubble gently for about a minute so the garlic turns fragrant and the sauce thickens slightly around the salmon. Spoon the glaze over the bites so every piece gets coated in that sticky, sweet-spicy goodness, then transfer everything to a plate.
While the salmon rests, bring a large pot of salted water to a rolling boil and cook the linguine according to the package directions until al dente. Reserve about half a cup of the starchy pasta water before draining, since it helps loosen the cheese sauce later. Drain the pasta and set it aside while you finish the sauce in the same skillet you used for the salmon.
In the same skillet, add the broth and heavy cream, scraping up any browned bits left behind from the salmon for extra flavor. Bring it to a gentle simmer, then stir in the parmesan and mozzarella a little at a time so the cheese melts smoothly instead of clumping. Season with a pinch of salt and pepper, and if the sauce feels too thick, splash in some of that reserved pasta water.
Add the cooked linguine directly into the skillet with the cheesy sauce and toss with tongs until every strand is coated evenly. Plate the pasta first, then top it generously with the honey butter salmon bites so they sit right on top rather than getting stirred in and losing their glaze. Finish with a sprinkle of fresh parsley and a lemon wedge on the side for that final bright touch.