Adjust rack to top position and preheat oven to 425 degrees. Bring a large pot of salted water to a boil. Wash and dry produce.

Core, deseed, and dice bell pepper. Halve, peel, and dice onion. Dice celery. Peel and mince or grate garlic. Zest and quarter lemon (for 4 servings, zest one lemon and quarter both). Grate Parmesan over a small bowl. Halve ciabatta lengthwise. Finely chop parsley. 

Once water is boiling, add linguine to pot. Cook, stirring occasionally, until al dente, 9-11 minutes.

Reserve 1 cup pasta cooking water (1½ cups for 4 servings), then drain.

While pasta cooks, place crab cakes on a lightly oiled baking sheet; bake on top rack until golden, 6 minutes.

Flip crab cakes and top each with ½ TBSP plain butter. Return to top rack and bake until warmed through, 6-9 minutes more.

While crab cakes bake, heat a drizzle of oil in a large pan (large high-sided pan or Dutch oven for 4 servings) over medium-high heat. Add bell pepper, onion, celery, Cajun Spice Blend, salt, and pepper. Cook, stirring, until veggies are softened and fragrant, 3-5 minutes.

Add garlic; cook, stirring, until fragrant, 30 seconds.

Stir in cream sauce base, stock concentrates, half the lemon zest, ⅓ cup reserved pasta cooking water (⅔ cup for 4), and juice from half the lemon. Bring to a boil, then reduce to a simmer; cook, stirring occasionally, until thickened, 4-6 minutes more.

Meanwhile, place 1 TBSP plain butter (2 TBSP for 4 servings) in a second small microwave-safe bowl and microwave until softened, 30 seconds. Add garlic herb butter and Parmesan to bowl; stir to combine.

Spread Parmesan garlic herb butter on cut sides of ciabatta. Place bread, buttered sides up, on baking sheet used for crab cakes. Bake on top rack until cheese melts and bread is toasted, 2-4 minutes.

Once garlic bread is cool enough to handle, slice diagonally.

Add drained linguine to pan with sauce; toss to combine. (TIP: If pasta seems dry, add more splashes of reserved pasta cooking water until desired consistency is reached.) Taste and season with salt and pepper.

Divide pasta between shallow bowls. Top with crab cakes, parsley, and remaining lemon zest. Serve with Parmesan garlic bread and remaining lemon wedges on the side.