Preheat oven to 350°F (176°C) and line cupcake pan with liners.
Mix flour, cinnamon, baking powder, and salt in a bowl, set aside.
Beat butter, oil, sugars, and vanilla until fluffy (2-3 mins).
Add eggs one at a time, mix until combined.
Add half of dry ingredients, mix; then add milk, mix.
Add remaining dry ingredients, mix until smooth.
Fill liners 3/4 full, bake for 15-18 mins, cool on rack.
Make filling: boil ingredients, set aside 1/2 cup, mix pecans, chill. Make frosting: beat butter, sugar, add filling, beat. Build cupcakes: core, fill, frost, sprinkle pecans. Enjoy!