Combine the flour, oats, brown sugar and pecans in a large bowl. Stir to combine.
In another bowl, whisk the eggs until foamy. Add the butter and vanilla, and mix well.
Add the wet ingredients to the dry until just combined.
Pour the batter into muffin tins lined with cupcake liners (fill each muffin tin about three-quarters full).
Bake in a preheated 350-degree F oven for about 20 to 25 minutes, or until a toothpick comes out clean.
Allow to cool on a wire rack before removing cups from muffin tins. Serve with a dollop of whipped cream, if desired.
