1In 3-quart saucepan, melt 1/4 cup of the butter over medium-high heat. Cook onion in butter 3 minutes. Add mushrooms; cook 3 minutes longer, stirring occasionally, until onion is tender and mushrooms are golden. Add wild rice and brown rice; cook and stir 1 minute.
2Stir in broth. Heat to boiling; reduce heat. Cover; simmer 45 to 50 minutes or until rice is tender and liquid is absorbed. Stir in remaining 2 tablespoons butter, the thyme, salt and pepper.