Starbucks' best-performing business unit -- the one that sells packaged coffee beans, ice cream and bottled Frappuccino in grocery stores -- is expanding into French and German stores this spring.

In partnership with Kraft Foods, it will sell ground coffee and single-serve inserts for Tassimo beverage machines.

Starbucks started selling through grocery stores in Europe two years ago, when it launched in the United Kingdom. Last year, it added Ireland and Switzerland.

Although Starbucks has only 48 coffee shops in France and 140 in Germany, grocery sales could prove lucrative.

The group that runs grocery sales boosted its operating profit by 12 percent last year, to $205 million.

By contrast, Starbucks' international stores took a 20 percent hit to operating profit, at $110 million.

U.S. stores fared the worst, earning only half of the previous year's operating profit. The figure was still big -- $528 million -- because the bulk of Starbucks' business is domestic (last U.S. store count: 11,537).