Pulse almonds in food processor 2 or 3 times or until chopped.
Add brown sugar and 1 tablespoon flour; process 5 seconds.
Add butter; pulse 5 times or until mixture is crumbly. Stir in oats; set aside.
Combine 2 cups flour and next 5 ingredients in a large bowl; add blueberries, tossing gently. Make a well in center of mixture.
Combine buttermilk, oil, and egg; add to flour mixture, stirring just until moistened. Spoon batter into greased muffin pans, filling two-thirds full, and sprinkle with oat mixture.