Cooking in a used tractor disc? It''s not a farmer''s prank. This practice, commonly called "discada" (Spanish for cooking in an agricultural disk or disco) is a culinary secret from Mexico. Just hearing the name conjures up memories from the streets of Durango, Mexico: The sizzle and scent of piping hot discada being scooped up by a street vendor, wrapped in warm, fresh corn tortillas and topped off with crisp cilantro and a splash of lime. Who would have thought that a used farm implement could yield such savory fare?

The disco''s humble origin began as a field tilling disc pulled by a tractor. After being unbolted from the tilling mechanism, the three or more holes in the disc must be welded shut. Sometimes a rim is welded along the top edge and often legs of varying length are attached to the bottom. The size of discos seem to vary, with contours ranging from extremely shallow to almost conical. What makes it so different from a traditional Asian wok is the thickness of the steel. While the wok''s relatively thin metal means food cooks fast and must be stirred often to avoid scorching, the heavy gauge metal of the disco allows the center--where the real sizzling happens--to remain piping hot, with a gradual decrease in temperature as food is placed nearer to the rim. This allows food away from the center to stay warm while not getting overcooked or burned.

My family''s first--and most authentic--discada experience was at a picnic in one of Durango''s beautiful public parks. Rather than the usual propane gas burner, the heating source of this disco was created the old fashioned way with mesquite hardwood started with a unique local kindling wood called oochote (literally a dense, oily wood so flammable that one match is all that is needed to start an entire blaze). From the first, we were fascinated with discada''s novel beginnings, its wide versatility, its delicious flavor, and its possibilities for artistic experimentation.

Upon returning home last summer, I was amazed to find that discos are in fairly wide use among migrant farm laborers in the Salinas Valley and in the Watsonville area. Most discos seem to be either brought from Mexico or constructed as a result of singular requests to local welders. For a heating source, charcoal is most authentic, but a simple attachment for any small propane tank that can make an adjustable flame is far easier and should be found at a local hardware shop.

It is difficult to pin down exactly what constitutes the "proper" ingredients for a discada. In an article in the L.A. Times, a writer who enjoyed discada in a restaurant in Catemaco, Mexico, declared: "Discada means a variety, an apt name for this dish of steak, green pepper, onions, bacon and pineapple tossed together." I found to my surprise that most of the local uses of discos seem to consist of deep frying various savory meats and vegetables. This discovery has led to my current definition for discada which is, "Just about anything in the world that can be cooked in a bowl-shaped, used agricultural disc."

Here is one way to cook discada compiled from our Mexico experiences:

As your disco is heating up (and you have passed out the icy Coronas to your guests), a few quesadillas can be placed around the edge of the disco as hors d''oevres. I also like to slice a huge onion in half to sizzle in the disco for flavoring and for munchable crispy onion slices.

First, a nice handful of bacon (about a half-pound) is thrown into the center of the disco. This provides the oil base for what follows (vegetable oil can be substituted instead of bacon). De-vein and finely chop two or three chiles poblanos and let them sizzle with the bacon (about 10 minutes). Push bacon and chiles out to spread evenly around the rim to form your first concentric circle. This is your chance to shine as a culinary artiste--the key is to vary the color of each remaining ingredient so that the final discada is made up of many varicolored rings.

Next, add two or three chopped onions, apply liberal salt/pepper and sizzle until tender. Again, push onions out in a circle inside the bacon. Each of the ingredients should be cooked separately and spread out in a ring, with a suggested order being: bell peppers (red, yellow and green), sausage, vegetables, beef, pork, chorizo and pineapple. Season with salt and pepper to taste, especially the meats. Skirt steaks can be salted and peppered and placed along the outside rim of the disco to cook slowly. Tortillas can be tossed on top of the concentric circles of food to heat from the steam of the cooking items (cooking al vapor in Spanish). This allows them to remain soft and moist and full of flavor.

When all is finished cooking, scramble the whole delicious ensemble together, spoon a few taste tests to check seasoning and serve in a hot corn tortilla (sometimes two tortillas are easier to handle) with lime and fresh cilantro. Fresh salsa, sour cream, Mexican beans, and guacamole with sweet tomatoes and lemon juice round out the meal nicely.

Although I could not find a single local restaurant that used a disco in food preparation (who will be the first?), I did discover a location where a disco can be purchased or even custom made. A local produce market called The Farm has good access to the disks (and the market is a great place for fresh produce). Take the Spreckels exit off Highway 68 and go west. Or call 455-2575 and ask for Frank Devine. Other than that, if you can locate an old tilling disk, any neighborhood welder should be able to create this unique cooking utensil--your ticket to delicious and festive backyard feasting.