Beat butter at medium speed with an electric mixer until creamy. Gradually add sugar, beating until light and fluffy. Add egg, beating well. Stir in honey, yogurt, and vanilla.
Combine flour and next 3 ingredients in a large bowl. Stir in oats and remaining ingredients; add to butter mixture, stirring well. Press mixture into a foil-lined 13" x 9" pan coated with cooking spray.
Bake at 350° for 35 to 40 minutes or until lightly browned. Cut into bars while warm. Cool completely in pan on a wire rack. Store in an airtight container up to 5 days.
Note: Always taste nuts and sunflower seeds before using in a recipe. If not stored properly, they become rancid quickly.