1. Preheat oven to 250°.
2. Line a jelly-roll pan with parchment paper; coat paper with cooking spray.
3. Heat oil in a large Dutch oven over medium-high heat. Add popcorn; cover and cook 4 minutes, shaking pan frequently. When popping slows, remove pan from heat. Let stand until popping stops. Uncover; add almonds.
4. Combine sugar, syrup, butter, and salt in a medium saucepan; bring to a boil. Cook 3 minutes, stirring occasionally. Remove from heat. Add peanut butter and vanilla; stir until smooth. Drizzle over popcorn; toss well. Spread mixture out onto prepared pan. Bake at 250° for 1 hour, stirring every 15 minutes. Cool completely.