Step 1
In a medium bowl, whisk together flour, baking powder, baking soda, and salt; set aside. With an electric mixer, or in the bowl of a stand mixer, beat peanut butter, vegetable oil, and granulated sugar together until light and fluffy. Add the eggs, one at a time, beating well after each addition, then beat in applesauce, milk, and vanilla. Add the flour mixture and beat until just combined. Divide batter evenly among lined cups, filling three-quarters full. Bake, rotating halfway through, until a tooth pick inserted into the center comes out clean, 18 to 20 minutes. Transfer pan to a wire rack to cool for 15 minutes, then remove the muffins and cool completely.
Step 2
When the muffins are cool, cut a 1-inch deep piece from the top of each with a pairing knife; do not discard pieces. Fill each with 1 teaspoon of jam, replacing cutout pieces. Dust with confectioners’ sugar.
Step 3
If making into cupcakes, omit confectioners’ sugar, and make frosting: beat together cream cheese, butter, peanut butter, and confectioners’ sugar until smooth. Using a small offset spatula, or the back of a spoon, spread cooled cupcakes with frosting and garnish the tops with a teaspoon of jam and chopped peanuts. Transport in a cupcake carrier.
Step 4
For the popcorn balls, lightly oil a large bowl and add corn, cereal, pretzels, and nuts; gently toss to combine. In a medium saucepan, combine sugar and corn syrup with 1/2 cup water. Cook over medium-high heat until mixture reaches 258 degrees on a candy thermometer, 6 to 8 minutes. Remove from heat and stir in butter, Worcestershire sauce, thyme, salt, and garlic powder until butter melted and mixture is smooth. Drizzle sugar mixture over popcorn mixture and stir until well coated and cool enough to touch, about 3 minutes.
Step 5
With oiled hands, press mixture into 3-inch balls. Place on a baking sheet lined with parchment paper to cool completely, about 10 minutes. Store balls, wrapped tightly in plastic wrapped, for up to 3 days. Use parchment paper bags to take on the go.