MEXICO CITY, Oct 24 (Reuters) - Mexican restaurant chain operator Alsea on Tuesday posted a 56% jump in net profit for the third quarter, boosted by particularly strong sales in its Mexico stores and a drop in some commodity prices.

Net profit hit 495 million pesos ($28 million), fueled by a robust expansion strategy.

Alsea, which operates chain stores including Starbucks , Burger King and Domino's Pizza, said revenues were up 11% in the quarter from a year earlier to 19.5 billion pesos, above forecasts by analysts polled by LSEG.

Sales growth in Mexico led the way at 17.8%, aided by a strong peso, offsetting a 6% fall in sales across South America.

In addition to Mexico, its largest market, Alsea operates in 10 other countries across Europe and Latin America.

In Europe, the company said it recorded a 62% drop in energy costs. Last quarter it had said it was nearing a deal on electricity supplies for stores in Europe.

Among Alsea's brands, Starbucks saw particularly strong growth, with a 25% jump in same-store sales globally, followed by a 16% sales increase in fast-food stores.

Adjusted earnings before interest, tax, depreciation and amortization (EBITDA) was up 13%, Alsea said in the filing.

"We continue with our solid organic growth, focusing on the expansion of our brands with greater growth and profitability potential such as Starbucks and Domino's Pizza," Chief Executive Armando Torrado said in the earnings statement.

The company said earlier this year that it was planning to invest $304 million across 2023, around a third of which would be spent opening at least 250 stores.

Alsea's shares year-to-date are up an eye-watering 60% as of market close on Tuesday, one of the best-performing shares on the Mexican stock exchange this year. ($1 = 17.4279 Mexican pesos at end-September) (Reporting by Isabel Woodford; Editing by Brendan O'Boyle and Leslie Adler)