Step 1: Preheat and Prep - Preheat your oven to 350 degrees. Spray a 12 count muffin tin generously with non stick cooking spray. This step matters more than you think because pecan pie filling loves to stick if you let it.
Step 2: Make the Crust - In a large bowl, add the flour, cold butter pieces, and brown sugar. Using a pastry cutter, fork, or clean hands, work the butter into the flour until fine crumbs form. It should look sandy and crumbly, not wet.
Step 3: Form and Bake the Crusts - Scoop about one quarter cup of the crumb mixture into each muffin cup. Press the crumbs down firmly and evenly to form a crust. Bake for 8 minutes, just until lightly set. Remove from the oven and let them cool slightly.
Step 4: Mix the Filling - In another large bowl, add the corn syrup, eggs, granulated sugar, and vanilla extract. Stir until completely combined and smooth. Add the chopped pecans and stir again so everything is evenly distributed.
Step 5: Fill the Cups - Carefully spoon the filling mixture over the partially baked crusts. Fill almost to the top, leaving a little space so they do not spill over while baking.
Step 6: Bake Low and Slow - Reduce the oven temperature to 275 degrees. Place the muffin tin back into the oven and bake for 30 to 35 minutes, until the centers are just set and no longer jiggly.
Step 7: Cool and Remove - Let the mini pies cool in the pan for 20 to 30 minutes. Run a butter knife gently around the edges, then carefully tip the muffin tin to release them. Serve warm or at room temperature.