Step 1: Cook the Pasta: First things first, get a big pot of water boiling. Make sure to generously salt your water – it's your first chance to season your pasta! Drop in your penne and cook it until it's just al dente, which means it still has a little bite to it. Usually, this is about 1 minute less than the package directions. Before you drain it, remember to scoop out about ½ cup of that starchy pasta water. Trust me, it’s liquid gold for your sauce! Then, drain the rest of your pasta and set it aside.
Step 2: Cook the Protein: While your pasta is doing its thing, grab your chicken or shrimp. Season it up nicely with a pinch of salt, pepper, and about 1 teaspoon of that fantastic Cajun seasoning. Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Once it’s shimmering, add your protein and sear it until it’s beautifully cooked through and golden. If you're using chicken, make sure there's no pink left. For shrimp, they'll turn opaque and pink. Once cooked, transfer it to a plate and set it aside for a moment. This ensures your protein stays tender and doesn't overcook.
Step 3: Sauté the Veggies: In that same skillet (don't clean it, those bits of flavor are precious!), add the remaining tablespoon of olive oil and the butter. Toss in your thinly sliced red and green bell peppers and the minced garlic. Sauté them for about 3-4 minutes, just until they start to soften up and smell amazing. You want them tender-crisp, not mushy!
Step 4: Build the Sauce: Now for the heart of our dish! Stir in the rest of your Cajun seasoning, the smoked paprika, and those red pepper flakes. Let those spices toast for about 30 seconds – this really brings out their flavor. You’ll notice the aroma filling your kitchen! Then, slowly pour in the heavy cream. Bring it to a gentle simmer, stirring occasionally. Once it starts to bubble lightly, stir in your grated Parmesan cheese until it melts and the sauce becomes wonderfully thick and creamy.
Step 5: Combine Everything: It's time for the grand reunion! Add your cooked penne pasta and the seared chicken or shrimp back into the skillet with the creamy sauce. Stir it all together, gently coating every single piece of pasta and protein with that incredible sauce. If the sauce seems a little too thick, now’s when that reserved pasta water comes in handy. Add it in small splashes, stirring until you reach your desired consistency. This is also a good time to taste and see if you need more salt or pepper.
Step 6: Garnish and Serve: Do a final taste test and adjust any seasonings as needed. This is where I sometimes add an extra pinch of cayenne if I’m feeling brave! For a bright finish, sprinkle with fresh chopped parsley or cilantro, and give it a squeeze of lime juice. Serve hot and watch it disappear!