Cast Iron Pork Tenderloin

Tender fennel-brined pork tenderloin seared and then roasted in a cast iron pan with butter, rosemary, and garlic.

You’ll love this flavorful, tender, and moist pork tenderloin recipe. The fennel and peppercorn brine provides extra flavor and moisture while the butter, rosemary, and garlic create a simple pan sauce.

Brine the pork for at least 4 hours but ideally up to a day in advance. Then, when it’s time to cook it you have a quick 30-minute meal.

Need sides to go with your pork? Try my Garlic Parmesan Orzo with Caramelized Shallots and Garlic Parmesan Asparagus. Or, for more options, visit my collection of side dishes to find just the right one!

Ingredients

Key Ingredient Notes

Pork Tenderloin – a long thin tender cut of pork.

Spice Blend – garlic powder, paprika, salt, and pepper add great flavor to the pork.

Rosemary – has a bright pine-like flavor that pairs well with the pork and flavors the pan sauce.

Garlic – deeply roasted garlic turns slightly sweet and flavors the pan sauce.

Butter – a bit of fat helps the pork brown nicely on the bottom as well as creating a simple pan sauce.

Why Brine The Pork

While pork tenderloins are tender cuts of meat, they can be prone to drying out when overcooked. Brining not only infuses flavor deep into the meat it also provides extra moisture and helps prevent the pork from drying out.

Brines are highly customizable. So long as they contain salt and sugar you can switch up the other flavorings. Fennel, peppercorns, and bay are classic flavors that pair well with pork but feel free to use what you like.

Why Cook In Cast Iron

Cast iron pans are thick and heat slowly but retain heat better than other pans which creates a nice deep even sear on meat. They are also convenient to use when cooking on the stovetop and then transferring to a hot oven since cast iron can be used for both.

Step By Step Instructions

Note: Full list of ingredients, their amounts, and instructions can be found in the recipe card below.

Step 1:

Bring water, kosher salt, granulated sugar, fennel seeds, black peppercorns, and a bay leaf to a gentle simmer over medium-high heat in a saucepan.

Reduce the heat to medium-low and continue simmering until the salt and sugar have dissolved into the water.

Step 2:

Remove the pot from the heat and add ice. Mix until the ice has completely melted.

Step 3:

Remove the silverskin and excess fat from the pork tenderloin by carefully cutting it away with a sharp knife.

Step 4:

Place the pork tenderloin in a container with a lid and pour the brine over the top. The brine should cover all or most of the meat. Add a bit more water if it doesn’t.

Brine in the fridge for 4 to 24 hours.

Step 5:

Preheat the oven to 400 degrees F.

Heat a large cast iron skillet over medium-high heat.

Step 6:

Remove the pork tenderloin from the brine and remove any fennel seeds and peppercorns. Pat the tenderloin dry with paper towels.

Note: Be sure to fully dry the tenderloin to get the best golden brown sear later.

Step 7:

Mix together garlic powder, paprika, salt, and pepper.

Brush the tenderloin with oil on all sides and then coat it with the seasoning mixture.

Step 8:

Sear the tenderloin for 1 minute on each side until deeply browned, for a total of 4 minutes.

Step 9:

Add the butter, rosemary, and garlic clove to the pan then transfer the pan to the preheated oven and bake for 15 minutes or until the internal temperature reaches 145 degrees F.

Note: I highly recommend that you use a meat thermometer to check the temperature. You want the tenderloin to just reach 145 degrees at the thickest part and then pull it from the oven. This will produce the most tender and moist results.

Step 10:

Allow the pork to rest for 5 to 10 minutes then serve warm along with the pan juices.

Tips & Tricks

• This recipe only calls for one garlic clove just to add flavor to the pork and butter. However, deeply roasted garlic tastes great with pork so if you’re a garlic lover, feel free to add as many cloves as you’d like.
• Make sure your pan is fully heated before adding the pork. This will take 5 to 10 minutes. To check, touch the end of the pork to the hot pan. If it sizzles, it’s ready to go.

Storage & Reheating

Storage

Store the pork tenderloin in an airtight container in the fridge for up to 4 days.

Reheating

Reheat over medium-low heat on the stovetop or in a 325-degree oven along with a tablespoon of butter until warmed through, about 7 to 10 minutes.

Freezing

Completely cool the pork tenderloin then wrap it in plastic wrap or foil and freeze for up to 6 months.

Allow the pork tenderloin to fully thaw in the fridge before reheating.

Subscribe to My Newsletter!

Get my newest recipes, kitchen tips and tricks, and the latest news right in your inbox!