Preheat the oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or grease the cups.
In a large bowl whisk together the all-purpose flour, granulated sugar, brown sugar, baking powder, and salt until evenly combined.
In a separate bowl beat the eggs, then whisk in the milk, melted butter and vanilla until smooth.
Pour the wet ingredients into the dry ingredients and gently fold until just combined; do not overmix.
Fold in 3/4 cup of the chopped pecans into the batter.
Divide the batter evenly among the 12 muffin cups, filling each about two-thirds full.
In a small bowl combine the corn syrup, 1/4 cup melted butter, and 1/2 cup brown sugar; mix until smooth. Spoon about 1 tablespoon of this pecan pie topping over each muffin.
Sprinkle remaining chopped pecans on top of each muffin for garnish.
Bake in the preheated oven for 16 to 18 minutes, or until a toothpick inserted into the muffin base (not the topping) comes out clean.
Allow the muffins to cool in the pan for 5 minutes, then transfer to a wire rack to cool slightly. Serve warm or at room temperature.
Notes
Store cooled muffins in an airtight container at room temperature for up to 3 days. Reheat briefly in the microwave or oven before serving for best texture.