Five-Peppercorn Fish Fillets

Firm white-fleshed fish fillets, like halibut, striped bass or grouper, take well to this simple, peppery butter sauce. A mix of different peppercorns — black, green, rose, Sichuan and Timut (from Nepal) — crushed to release their flavor and aroma, creates a seasoning that is sweet and spicy, but not "hot." The Sichuan and Timut pepper are quite floral and have a somewhat tongue-numbing quality. Most spice merchants will offer many kinds; feel free to use just one or two, or to refine the mixture to your own taste.

INGREDIENTS
1 teaspoon black Tellicherry peppercorns
1 teaspoon dried whole green peppercorns
1 teaspoon rose (pink) peppercorns
1 teaspoon Sichuan peppercorns
1 teaspoon Timut peppercorns
4 tablespoons unsalted butter
12 fresh sage leaves
 Salt
4 boneless halibut, sea bass or grouper fillets, about 6 ounces each
 All-purpose flour, for dusting
2 tablespoons olive oil
½ teaspoon lemon zest or lime zest
1 tablespoon lemon juice or lime juice
 Tender parsley or watercress sprigs, for garnish

PREPARATION
Put all the peppercorns in a small dry skillet over medium heat. Warm them, shaking the pan, until fragrant, a minute or two. Cool, then transfer to a mortar or electric spice mill. Pound with a pestle or pulse in the spice mill, shaking, to obtain a coarse powder. Reserve 1 tablespoon peppercorn mixture and store remainder.
Melt butter in a small saucepan over medium-high heat. Add 1 tablespoon peppercorn mixture and swirl pan until foamy and beginning to brown. Add sage leaves and a good pinch of salt. Set aside, off the heat.
Season fish fillets on both sides with salt and dust very lightly with flour. Put a wide cast-iron skillet over high heat and coat bottom with olive oil.
When oil is hot, lay the fillets in the pan and let them brown gently, turning down heat as necessary. After 2 minutes, flip fish and cook until no longer translucent when probed, about 2 minutes more. Transfer fish to a warm platter or individual plates.
Return butter sauce to stove over medium-high heat. Bring to a simmer and add citrus zest and juice. Stir well, then spoon sauce over fish and serve immediately.