Pesto Compound Butter over Grilled Swordfish with Slow-Roasted Heirloom Tomatoes & Peppers
Aug 15, 2019, Updated May 13, 2025
A Restaurant Quality dish. Make delicious Pesto Compound Butter in minutes! Slice and add to just-off-the-grilled local swordfish ~ melts into a dreamy sauce. Slow Roasted Vegetables soften and are intensely sweet, adds a pop of color.

In this recipe you will explore a few recipes: Pesto Compound Butter, Grilling Fresh Swordfish, Slow Roasting Heirloom Vegetables – and how to make them special with a few extra add-ins (add warm pasta for a heartier dish.)

Compound butters: French: beurre composé, are mixtures of butter and supplementary ingredients. Primarily, they are used to enhance flavor in various dishes, in a fashion similar to a sauce. Keep frozen and slice when using.

If not making this dish in peak summer season ~ Use colorful cherry tomatoes on-the-vine and miniature colorful peppers (both readily available.)





Slow roasting concentrates flavors… sweet!


Other Flavoring Ideas for Compound Butter:
~ Use these Slow Roasted Vegetables, mince the mixture and add to butter with minced fresh herbs of your choice.
~ Jalapeño Lime Butter
~ Roasted Garlic and Chives
~ Blackened Hatch Chili with Smoked Paprika
~ Roasted Zucchini with their blossoms
~ Honey (or Maple) Cinnamon Butter (can add toasted nuts)
~ Blueberry Lavender, try other fruits such as peaches, apricots and strawberries. Use minced fresh fruit AND add pulverized dehydrated fruit for and extra layer of flavor and brighter color.
Enjoy these flavors of summer – this is a very special recipe!
Karen
Pesto Compound Butter over Grilled Swordfish with Slow-Roasted Heirloom Tomatoes & Peppers

Ingredients
Compound Pesto Butter:
- 1 stick unsalted butter, organic – room temperature (4 ounces)
- 1 1/2 tablespoons pesto
- 1/8 teaspoon sea salt, I’ve used Himalayan
Swordfish:
- 28 ounces fresh swordfish steak, cleaned and dried cut into 4 pieces
- 1 1/2 teaspoons extra virgin olive oil
- 1 teaspoon cajun seasoning, salt free
Roasted Tomatoes & Peppers:
- 20 small heirloom cherry tomatoes, such as sun gold, black cherry and juliet hybrid
- 1 3/4 cups sliced peppers, choose a few colors
- 1 teaspoon extra virgin olive oil
- 2 big pinches each: sea salt and freshly ground pepper
- 1/2 teaspoons Italian seasonings, crushed with your fingertips
- 2 tablespoons extra virgin olive oil
- 1 tablespoon finely chopped fresh shallots
- 1/2 teaspoon finely grated fresh garlic
- 1 pinch cayenne pepper
- 2 tablespoons petite basil leaves, for garnish
Instructions
Recipe Overview:
- There are three elements to this recipe. You may choose just to grill the Swordfish and top with the Pesto Compound Butter. Adding the roasted Tomatoes & Peppers create a restaurant quality dish!
Make the Pesto Compound Butter:
- Really simple… the details: In a medium sized bowl, cream the butter with a small whisk or rubber spatula. Add pesto and sea salt. Stir well until creamy and very well mixed. Cut a piece of waxed paper 10" long, set on your work surface. Add the pesto butter in the shape of a log, 10" long – roll up to incase: You are looking to form an evenly shaped cylinder. Twist the sides (see photo in BLOG) – this will firm up and shape the roll. Place on a plate or small rimmed pan and place in the freezer until very cold and firm, at least 2 hours. After, place in a freezer bag and slice when you need some. WILL HAVE EXTRA for another recipe.
Roast Heirloom Tomatoes & Peppers:
- Preheat oven to 300 degrees. Add a sheet of parchment paper to cover a rimmed sheet pan. Drizzle 1 teaspoon extra virgin olive oil on the pan. Clean, dry and cut cherry tomatoes in half. Cut peppers into 1" long x 1/2"wide pieces. Add to pan (tomatoes cut-side up) with salt, pepper an Italian seasonings. Rub in to coat. Slow roast in over for 30 – 40 minutes until somewhat shriveled and dried out, and just starting to color. Serve the vegetable as is, or add to this bowl, below.
Seasoning the Tomatoes and Peppers:
- In a medium sized bowl, add 2 tablespoons extra virgin olive oil, 1 tablespoon finely chopped fresh shallots, 1/2 teaspoon finely grated fresh garlic and a pinch of cayenne pepper. Stir together – add the warm roasted tomatoes and peppers, give big toss – taste for seasonings. Great with Pasta too! Option: add to 1 1/2 cups warm pasta into the bowl and toss.
Grill Swordfish:
- Heat grill to medium high, brush with neutral oil. In the meantime, add swordfish to a plate, top with 1 1/2 teaspoons of olive oil, rub in cajun seasoning. When grill is hot, add swordfish and let develop strong grill marks on underside. Turn over, reduce heat to medium and cook until swordfish is cooked through (about 4 – 5 minutes per side, depending on thickness; 130 – 140 degrees internal.) Remove to a clean plate. Immediately – CUT 4, 1/2" PIECES OF BASIL COMPOUND BUTTER (frozen) and top each piece of the warm swordfish. Butter will melt into a sauce. Sprinkle swordfish with sea salt and serve with: Slow-Roasted Tomatoes and Peppers (with pasta optional.)
- Garnish with petite basil leaves all over and serve.
Roasted Tomatoes & Peppers:
Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.