Pumpkin Cheesecake Swirl Muffins

INGREDIENTS

• 1 (15 ounce) can pumpkin
• 1/4 cup vegetable oil
• 2 large eggs
• 1 cup sugar
• 1 teaspoon vanilla
• 1 1/2 cups all-purpose flour
• 1 teaspoon baking powder
• 1/2 teaspoon baking soda
• 1/2 teaspoon ground cinnamon
• 1/2 teaspoon ground ginger
• 1/2 teaspoon ground nutmeg
• 1/8 teaspoon ground cloves
• 1/2 teaspoon salt
• 1/4 teaspoon fresh ground black pepper
• 8 ounces cream cheese, at room temperature
• 1 large egg yolk
• 5 tablespoons sugar
• 1/8 teaspoon vanilla extract
• chopped nuts (walnuts, pecans) (optional)