What garlic mustard pesto does to catfish

Garlic mustard pesto turns mild catfish into something bright and alive. The pesto — made from foraged or garden garlic mustard, garlic, nuts, oil, and acid — cuts through the fish's richness without overwhelming it. Catfish's tender flesh takes on the pesto's sharp, slightly peppery character while staying moist and delicate. You brush or dollop the pesto onto the fish before or after cooking, or fold it into the flesh itself if you're filleting.

This is a spring dish. Garlic mustard grows wild in most of North America from March through May, with tender leaves that taste like a cross between arugula and horseradish. If you forage it, you're also managing an invasive plant that crowds out native wildflowers — a small act of land stewardship while you cook dinner. If you don't forage, you can substitute arugula, watercress, or even spinach with a pinch more mustard powder, though the result will be gentler.

Key Takeaways

  • Garlic mustard leaves are foraged in spring and have a sharp, peppery bite that complements catfish's mild, buttery flesh.
  • The pesto is made by blending garlic mustard, garlic, nuts (pine nuts or walnuts work), lemon juice, and olive oil into a thick paste.
  • Catfish fillets cook quickly — 8 to 10 minutes in a hot pan — and the pesto can go on before cooking, after, or both.
  • If you cannot find garlic mustard, arugula or watercress make a reasonable substitute, though you should add a small amount of mustard powder to match the bite.

Foraging and preparing garlic mustard

Garlic mustard grows in disturbed ground, along stream banks, in open woods, and at the edges of fields. The plant is a biennial: in its first year it makes a rosette of heart-shaped leaves close to the ground; in its second year it sends up a flowering stalk with small white flowers and seed pods. Pick the tender leaves from first-year plants or the lower leaves of second-year plants before the flowers open. Leaves are best in early spring when they're young and tender.

Wash the leaves and spin them dry. Taste one raw — it should be sharp and slightly hot, like a cross between mustard greens and wasabi. If you've picked very young leaves, you can use them whole. Older leaves are tougher; tear or chop them into smaller pieces. You'll need about two cups of loosely packed leaves for a pesto that serves four people with catfish.

If you're buying greens instead, use two cups of arugula or watercress. Watercress is closer in character to garlic mustard — it has a similar bite and grows in similar places. Arugula is milder but more widely available. Either way, wash and dry them thoroughly before blending.

Making the pesto

Combine two cups of garlic mustard leaves (or substitute), two cloves of garlic (minced or sliced), one-half cup of nuts (pine nuts, walnuts, or almonds all work), the zest and juice of one lemon, one-half teaspoon of salt, and one-quarter teaspoon of black pepper in a food processor or blender. Pulse until the mixture is broken down but still has some texture — you want it to look like wet sand, not a smooth paste.

With the machine running, pour in three-quarters of a cup of olive oil in a thin stream. Stop when the pesto reaches the consistency you want: thicker if you plan to dollop it on the fish, looser if you want to brush it on. Taste and adjust the salt and lemon juice. The pesto should taste sharp and alive, not muted. If it tastes flat, add more lemon juice or a pinch more salt.

You can make this pesto up to two days ahead. Store it in a covered container in the refrigerator. If the oil separates, stir it back in before using. The pesto will darken slightly as it sits — this is normal and does not affect the flavor.

Preparing and cooking the catfish

Use catfish fillets, skin-on or skinless depending on your preference. Pat them dry with paper towels. Heat two tablespoons of olive oil or butter in a large skillet over medium-high heat until it shimmers. Season the fillets on both sides with salt and pepper.

Place the fillets skin-side up in the hot pan (or presentation-side up if skinless). Cook without moving them for four to five minutes, until the bottom is golden and releases easily from the pan. Flip and cook for another three to four minutes, until the flesh is opaque throughout and flakes gently when pressed. The exact time depends on the thickness of your fillets — thinner fillets cook faster.

You have three options for the pesto: brush it onto the fillets in the pan during the last minute of cooking, spoon it onto the cooked fish just before serving, or do both. Brushing it on during cooking lets the pesto warm through and its flavors meld with the fish. Spooning it on after cooking keeps the pesto's bright, fresh character. Many cooks do both — a thin layer during cooking, a generous dollop on top at the table.

Serving and pairing

Serve the catfish on a bed of spring greens, with crusty bread to soak up the pesto and pan juices. A simple salad of tender lettuces and radishes works well. If you foraged the garlic mustard, you might forage the salad too — chickweed, young dandelion greens, and violet leaves all appear in spring and pair naturally with the pesto's character.

For wine, choose something crisp and acidic: a Sauvignon Blanc, Pinot Grigio, or dry Riesling. The acidity echoes the lemon in the pesto and cuts through the richness of the fish and oil. Beer works too — a pale ale or pilsner will do the same job.

Leftover pesto keeps for three days in the refrigerator and is good on grilled vegetables, stirred into pasta, spread on sandwiches, or spooned over eggs. If you have extra catfish, cold fillets with pesto make an excellent lunch the next day.

Scaling the recipe and storing pesto

The pesto recipe above makes about one cup, enough for four catfish fillets with some left over. If you're cooking for two, halve everything. If you're cooking for six or eight, double it — the pesto keeps well and you'll find uses for it.

To store pesto longer than three days, freeze it in ice cube trays. Once frozen, pop the cubes into a freezer bag and label them with the date. Each cube is roughly two tablespoons. Thaw at room temperature or add directly to a warm pan. Frozen pesto will keep for up to three months. The texture becomes slightly grainier after thawing, but the flavor remains sharp and true.

Frequently Asked Questions

Can I use store-bought pesto instead of making my own?

Yes, though the result will be different. Commercial basil pesto is milder and sweeter than garlic mustard pesto. If you use it, choose a pesto labeled "genovese" or one with a short ingredient list. Spoon it on after cooking rather than during, so the heat doesn't dull its flavor further. You might also add a squeeze of lemon juice to brighten it.

What if I can't find garlic mustard or don't want to forage?

Arugula and watercress are your best bets — both are sold year-round at most grocery stores. Watercress is closer in character to garlic mustard. Add one-quarter teaspoon of mustard powder or a small pinch of wasabi powder to the pesto to approximate the bite you'd get from garlic mustard. Taste as you go.

How do I know when the catfish is done cooking?

The flesh should be opaque all the way through and flake gently when you press it with a fork. If you have a meat thermometer, catfish is done at 145°F (63°C) in the thickest part. Overcooked catfish becomes dry and tough, so err on the side of slightly underdone — it will continue cooking as it rests.

Can I bake or grill the catfish instead of pan-frying?

Yes. To bake, place fillets on a parchment-lined sheet, brush with oil, season with salt and pepper, and bake at 400°F (200°C) for 10 to 12 minutes. Brush with pesto in the last minute or spoon it on after. To grill, oil the grates well, cook over medium-high heat for three to four minutes per side, and add pesto after cooking to avoid charring it.

Does the pesto need to be warm when I serve it?

No. Pesto is good warm, room temperature, or cold. If you make it ahead and refrigerate it, let it sit out for 15 minutes before serving so the olive oil softens and the flavors open up. You can also warm it gently in a small pan over low heat, stirring constantly so it doesn't brown.