Preheat oven to 350º F. Spray a Mini Fluted Tube Pan (12-Cavity) with baking spray.
Mix flour, baking powder and salt in a mixing bowl until well combined. Set aside.
With an electric mixer, or stand mixer fitted with a paddle, beat the butter and sugar together on high speed until creamy, about 2 minutes. Scrape down the sides and up the bottom of the bowl as needed.
Reduce mixer speed to low, add the eggs one at a time, then pumpkin puree and lemon zest. Beat on medium-high speed until combined. Scrape down the sides and up the bottom of the bowl as needed. With the mixer running on low speed, slowly add the dry ingredients. Beat everything just until incorporated. Do not over-mix. Foil in the apples.
Spoon batter into pan, filling each bundt cake cavity 2/3 full.
Bake for 20-25 minutes or until the cakes are lightly golden and spring back when lightly poked with your finger. Remove from the oven and allow to cool inside the pan for 5 minutes. Then transfer to a wire rack and let them cool completely.