The most important meal of the day

Breakfast is the fastest growing sector in the fast food industry. And the competition is heating up. First McDonald's upgrades its coffee, then Starbucks introduces a McMuffin clone, an advance made possible by a super duper, high-heat oven.

In samples from around New York City last week, both the Starbucks sandwiches and Egg McMuffins offered the virtues of any good egg sandwich: the salty, savory contrast of soft egg, molten cheese and chewy bread. Both the ham and the sausage patty at Starbucks were meatier and less greasy than the meats at McDonald’s, and there was surprisingly little difference in the taste of the eggs — both had almost no flavor.

As the Starbucks sandwiches cooled, the texture changed noticeably (as is often the case with microwaved sandwiches), leaving tough bread and bacon, rubbery cheese and spongy egg.

“Starbucks is making a big bet on those ovens,” Mr. Miner said. About 20 percent of its stores now have the ovens. “They are not cheap, and it’s a big hulking thing to put on the counter, not to mention training your staff to use it.” At one Manhattan Starbucks last Friday, workers were so busy heating sandwiches that the store actually ran out of drip coffee.