I love seafood chowders of all kinds, and I cook them often. What had always made this delectable soup possible in just 20 minutes flat was a simple, ingenious ingredient: Bouillon cubes flavored with fish that added a long-simmered depth in a flash.

Imagine my dismay when these little gems suddenly disappeared from the supermarket. Knorr, the only manufacturer of fish cubes we've been able to find, has discontinued them from the main product line. Off I went in search of a suitable substitute.

The good news — make that great news — is that I found an even more wonderful ingredient called clam base. This is essentially clam-flavored bouillon paste that's sold in a jar alongside other bouillon. Better Than Bouillon is one national brand. Check the company's Web site at superiortouch.com/btb.htm.

Clam base, as it turns out, is more flavorful than fish bouillon. But if you want to use fish cubes, Knorr says they're still available in the company's Hispanic product line, under the name Caldo de Pesco. You can also use the Knorr shrimp bouillon, Caldo con Sabor de Camaron, in today's seafood chowder. My brother-in-law Roger, an excellent cook who lives in New York, was visiting when I tested my latest rendition of seafood chowder with clam base. He eyed me with suspicion when I boasted I could produce the soup in a mere 20 minutes. When the kitchen timer rang and I scooped up a taste for Roger, his eyebrows shot up in surprise.

"That's terrific," he said. "I wouldn't have believed it if I hadn't seen it myself."

Clam base. Believe it!

Menu suggestion: Seafood Chowder in a Flash

Sliced tomatoes

Corn muffins

SEAFOOD CHOWDER IN A FLASH

Start to finish: 20 minutes

Cook's notes: Clam base is sold alongside bouillon cubes. You may substitute 2 teaspoons lobster base or 1 Knorr fish or shrimp bouillon cube. If you can't find these ingredients, substitute 2 chicken bouillon cubes as a last resort, but the flavor won't be quite the same. With any of these substitutions, follow the directions in Step 1.

Already-peeled cooked shrimp can be substituted. Add them with the corn in Step 4.

2 cups water

2 teaspoons clam base (see Cook's notes)

2 tablespoons butter

1 large onion (for about 1 cup chopped)

2 large red potatoes

8 ounces firm white fish, such as tilapia, defrosted if frozen

8 ounces already-peeled raw shrimp, defrosted if frozen (see Cook's notes)

1 can (6 1/2 ounces) minced or chopped clams

1 teaspoon Worcestershire sauce

1/4 teaspoon dried thyme