The return of the Noonday onion to the market and table is as sure a sign of the season as azaleas and Easter lilies (though perhaps not as poetic). The number A&M gave to its Texas version of the honeyed Vidalia onion strain is 1015; Noonday onions are 1015s grown in Noonday County in East Texas, where the soil seems to be particularly conducive to sweet onions. Why are they so good? As my sister the chef says in her characteristically down-to-earth way, "It has to do with the dirt." 8.0 serves a 1015 stuffed with blackened crawfish in cream with jalapeno tartar sauce. Parigi's chef, Jack Johnston, concocts a spring vegetable salad of grilled portabellos and Noondays with roasted sweet potato disks in a spunky garlic-lemon vinaigrette with lots of Dijon. For those who'd appreciate a simple, do-at-home suggestion, I used to know someone who ate onion sandwiches--just thinly sliced sweet onion, homemade mayonnaise, salt, and a generous sprinkling of black pepper. On white bread, of course.