Make-Ahead Slow Cooker Method: Combine first 7 ingredients in a 4-quart electric slow cooker; cover and cook on HIGH setting 3 hours. Drain excess liquid, if necessary. Fluff rice with a fork; sprinkle with almonds, if desired.
Cooktop Method: Melt butter in a 2-quart saucepan over medium heat. Stir in rice, cook, stirring occasionally, 5 minutes. Add mushrooms and next 4 ingredients, bring to a boil. Cover, reduce heat, and simmer 1 hour and 5 minutes or until rice is done; drain excess liquid, if desired. Fluff rice with a fork; sprinkle with almonds.