Grilled Pork Tenderloin with Blackberry Gastrique

This Grilled Pork Tenderloin with Blackberry Gastrique is an absolute stunner! Pork tenderloin is the blank canvas in this dish and the gastrique is the star – sweet, tart, velvety and complex. Learn the technique to make this classic French sauce in this post and you can use it all year long to make incredibly impressive and delicious dishes!

I know your first question is going to be ‘what the heck is a gastrique’?! The short answer: it’s a sauce! The slightly longer answer: a classic French sauce that is sweet and sour, complex and rich, and unbelievably delicious.

I first learned how to make a gastrique in culinary school and it was unlike anything else I had ever made in the sauce realm. Making a caramel and adding vinegar?!

And when I tasted it? Wowsers.

It was a cherry gastrique and it was served with duck. The combination was absolutely magical.

Read on for all of the details and be sure to watch the video below for step-by-step instruction. This is a sauce you’re going to want to add to your repertoire.

Plus, you can flex that you know how to make a gastrique!

Need a side dish to serve with it? How about this Roasted Sweet Potato Puree, Classic Potatoes Anna, or this Pumpkin Orzo?!

What is a Gastrique?

Great question!

A gastrique is a classic French sauce originating all the way back in the 1600s. Its texture is more like a glaze and its flavor profile is tart, but also sweet, assertive, and complex.

I learned how to make this sauce in culinary school and always like to use it to take advantage of seasonal fruit and pair it with grilled meats and vegetables.

In its most simple form, it can be made with just sugar (or honey) and vinegar. You simply caramelize sugar and then add vinegar. It is then simmered until it reduces to a beautiful glaze.

But in this jazzed-up version, I love adding the flavor that the reduced wine brings, as well as the fresh fruit. It’s spectacular! For another version, check out my Cranberry Gastrique!

Recipe Ingredients

You’ll need the following ingredients to make this Pork Tenderloin with Blackberry Gastrique:

Ingredient Notes & Substitutions

The ingredients to make this pork tenderloin are easy to find and readily available at most any grocery store.

Here are a few ingredient notes:

Pork tenderloin: A muscle located on both sides of the pig’s spine, pork tenderloin is a lean muscle that isn’t really used. What does that mean? It means the meat doesn’t have much fat, is tender, which is good, but it also means it’s lean, which means the flavor isn’t deep. Therefore, sauces, rubs and marinades become key for this cut of meat. It also has a layer of silver skin over part of it that should be removed before cooking, as it is very difficult to chew through. Pork tenderloin is easy to find at your local supermarket, is affordable, and is often sold in pairs. You will need to two in this recipe.

Red wine: This recipe calls for a dry red wine. The only other criteria is that it should be drinkable. Why? Because we’re going to reduce it by half, and if you start with something that doesn’t taste good, guess what happens when you concentrate it? It really doesn’t taste good!! I used a big jammy California cabernet sauvignon, but you could use something a little lighter if you prefer – a merlot or malbec would make a fine substitute, but feel free to use what you like or have. Although the alcohol is cooked off in this recipe, if you prefer not to use it, you could substitute a berry-flavored loose leaf tea that you reduce, just as you would the wine (I made this exact substitution in a recipe I created for a dear friend of mine who wrote Tea for Dummies ).

Blackberries: This time of year, berries are amazing, and in particular, I love blackberries and the way they pair with the red wine in this recipe. If you prefer, you could substitute with blueberries.

Sherry vinegar: If you know me at all, you know my love for sherry vinegar and what I consider to be the perfect amount of acidity and flavor. It’s perfect in this recipe, but you could also substitute a good quality red wine vinegar if you need to.

Let’s Make the Grilled Pork Tenderloin Together: STEP BY STEP

Steps 1 & 2:

Begin by removing the silver skin from the tenderloins. To do this, insert a boning knife under the silver skin, point the blade upward as you push it down the length of the silver skin. Pointing the blade upward will keep you from gouging the flesh of the meat and helping you to only remove silver skin.

Next, reduce the wine by half by bringing it to a boil and then reducing to a simmer. Set aside.

Then, in another clean dry saucepan, add the sugar over medium heat and stay close.

Steps 3 & 4:

As soon as you see the edges of the sugar start to caramelize, stir around the sugar so that the color is evenly distributed.

Then, turn the heat off and carefully add the vinegar. The sugar may harden, but don’t worry, it will all melt again. Turn the heat back on to medium.

Steps 5 & 6:

Add the reduced red wine and the blackberries. Then, let it simmer until it reduces and thickens.

Steps 7 & 8:

You will know it has reached the right consistency when you can draw a line on the back of the spoon and the sauce doesn’t come back together. Season with salt and pepper and add a squeeze of lime for balance and set aside.

To prepare the tenderloins for grilling, brush them with avocado oil and season them generously with kosher salt and black pepper.

Steps 9 & 10:

Preheat the grill over high heat. Then, reduce the heat to set the grill up for direct (medium high) and indirect heat (low).

Begin by searing the tenderloins over direct heat for about a minute on each of the four sides of the tenderloin. Then, move them over to the indirect heat (fat side facing the direct heat side) to finish cooking through. You will know the the tenderloins are done when they reaches 145 degrees, but I recommend taking it off before then, as it will continue to cook a few more degrees while resting.

Storage & Reheating

STORAGE: Store the pork tenderloin and sauce separately, in airtight containers, in the refrigerator for up to 4 days.

REHEATING: To reheat the pork tenderloin, place it on a sheet pan with a splash of water. Cover it with foil and place in the oven at 350 degrees until warmed through. Reheat the sauce in a sauce pan on the stove until warmed through.

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