Heat oven to 300°F. Line 1 large (17x14-inch) cookie sheet or 2 (15x10x1-inch) pans with foil; spray foil with cooking spray. In large bowl, mix both cereals, the oats and almonds; set aside.
In 1-quart saucepan, heat butter, brown sugar and syrup over medium heat, stirring frequently, until butter is melted and mixture boils. Pour over cereal mixture; stir until well coated. Spread mixture evenly on cookie sheet with rubber spatula until about 1/2 inch thick.
Bake 35 to 40 minutes or until almonds are golden brown. Cool completely, about 15 minutes. Break into pieces with fingers. Store in tightly covered container.