Stir together the butter, maple and vanilla and pour into the processor. Pulse the processor to mix well, then transfer the oat mixture to a large bowl. Squeeze and knead the mixture, if needed, to make a dough. Chill for 30 minutes. Use a tablespoon to scoop 2 rounded tablespoons into each muffin cup. Use your fingers to press the dough into the bottom and evenly up the sides about 3/4 of an inch. Bake for 20 minutes.