Burger King Holdings Inc. (BKC) is comfortable testing new products like smoothies and soft-serve ice cream, but doesn't plan any big product line extensions like its top competitors are making, Chief Executive John Chidsey said Tuesday in an interview.

Burger King's key product innovations comes not with what, but how it cooks food. In February, the chain plans to begin nationwide advertising for its "XT Steakhouse" burger, a thick burger cooked on a "batch broiler" whose capabilities include products like ribs.

"Innovate around the edges, but to go any further astray, I don't see the need to do that," Chidsey told Dow Jones Newswires.

Burger King's top competitors, McDonald's Corp. (MCD) and Wendy's/Arby's Inc. (WEN), are making big splashes into new product lines, which they credit for improving sales. McDonald's has launched its premium coffee line, McCafe, while Wendy's recently began selling boneless wings.

Burger King, the second-largest hamburger chain in the world behind McDonald's based on sales, sees its batch broiler as a "game changer" that it says can blur the line between the food quality at its stores and that of casual-dining chains.

Highlighting premium products from its batch broiler will come after Burger King has for the last couple months leaned heavily on the value switch in its ads by promoting the $1 Whopper Jr. and offering coupons for $1 double cheeseburgers. The strategy has hurt the average check but helped to increase traffic from lows hit in May.

Unemployment has been a big culprit in sales declines, especially given that it affects Burger King's so-called "Superfans," 18- to 35-year-old men who eat at burger chains nine or more times a month, disproportionately. Still, the chain will continue to try to capture more visits from these customers than focus on another demographic.

"It's easier to try to get one more visit from them than try to find lapsed users or other segments," Chidsey said.

Burger King still expects at least another six months of "soft" sales as unemployment concerns weigh after reporting Tuesday a 2.4% decline in fiscal fourth-quarter global same-store sales, including a 4.5% drop in the U.S. and Canada.

Earlier Tuesday, Burger King reported a 16% increase in its fiscal fourth-quarter profits, helped by a low tax rate and improving margins. Per-share earnings of 43 cents topped low expectations, and helped Burger King shares rally $1.21, or 6.9%, in recent trading, to $18.87.

While withholding fiscal 2010 earnings guidance, Burger King said it would slow new store openings in the coming year to between 250 and 300, largely as development projects around the world are delayed.

"We're not going to build on an outer pad without Wal-Mart or Lowe's being a traffic generator," Chidsey said.

-By Paul Ziobro, Dow Jones Newswires; 212-416-2194; paul.ziobro@dowjones.com