Recipe Summer squash gratin with butterfish

I've had the Sunday Suppers at Lucques cookbook for years and I think I've cooked out of it one other time.  So when it came time to do another recipe, I knew I could push myself and cook something simple - a gratin, but from a difficult cookbook.  But really this cookbook isn't difficult - the recipes just have lots of ingredients, steps, and use a lot of dishes.  So technically difficult, no.  Time and labor intensive, yes.  But this recipe wasn't so time-consuming when I got down to it.

I picked up all the ingredients at Whole Foods and was really looking for halibut, but choose this Black Cod/ Sablefish/ Butterfish that had a green rating.


  • 2 lbs summer squash
  • 1.5 fresh breadcrumbs (I used gluten-free cubed croutons)
  • 4 tablespoons unsalted butter, ,divided
  • 3/4 cup shallots or sweet onions
  • 1 teaspoon minced garlic, about 2 cloves
  • 1 tablespoon thyme leaves
  • 1 cup Gruyere, grated
  • salsa verde
    • 1 teaspoon fresh oregano
    • 1 tablespoons fresh mint
    • 1/2 cup fresh parsley
    • 1/2 cup olive oil
    • 1 clove garlic
    • 1 anchovy
    • 1 teaspoon capers
    • lemon
    • 1.5 lbs of Butterfish or other flakey white fish
    • 2 tablespoons olive oil

Preheat oven to 400 degrees

Cut squash about 1/8" thick, toss it with a pinch of salt in large bowl and let sit.

Meanwhile, make salsa verde by crushing oregano, mint, and parsley with mortar and pestle (or in food processor).  Transfer herb paste into small bowl with olive oil, then crush 1 clove garlic and anchovy into paste, adding it to herb mixture, finally slightly crush the capers before adding to herb mixture.  Stir together, adding a squeeze of lemon to taste and black pepper.  Set aside.

In cast-iron skillet swirl 3 tablespoons of butter until brown and toasty, turn off heat and toss in breadcrumbs (or gluten-free croutons like I used) coating with butter.  Set aside skillet.

Drain squash of liquid on bottom of bowl and add shallots, garlic, thyme, 1/2 cup salsa verde, cheese, and 1/2 of the breadcrumbs - toss to combine.

Place squash mixture in 9 x9 gratin pan and top with remaining breadcrumbs.  Bake 35-40 minutes until squash is tender and breadcrumbs are golden brown.

Prepare the fish into 4 equal portions (about 6 oz each) sprinkle with salt and pepper and return to fridge.

When there are about 10 minutes left on the gratin, remove the fish from the fridge.  Heat up the same cast-iron skillet with 1 tablespoon butter and 2 tablespoons of olive oil.  When the skillet is just smoking, place fish skin-side down and use a large spoon to spoon the butter and olive oil on top of the fish.  Cook for approximately 4 minutes, continually spooning the hot oil on the fish to baste it.  Fish should be opaque and just flakey.

Top with a little remaining salsa verde.  Serve.

Recipe adapted from Sunday Suppers at Lucques by Suzanne Goin

Recipe Summer Squash Gratin with Butterfish on Capella Kincheloe Interior Design