Pulse almonds 2 or 3 times in a blender or food processor until chopped. Add brown sugar and 1 tablespoon flour; process 5 seconds. Add butter; pulse 5 or 6 times or until mixture is crumbly. Stir in oats; set aside.
Combine 2 cups flour and next 5 ingredients in a large bowl; make a well in center of mixture.
Whisk together buttermilk, oil, and egg; add to flour mixture, stirring just until moistened.
Toss blueberries with remaining 2 tablespoons flour; gently fold into batter. Spoon batter into greased muffin pans, filling two-thirds full; sprinkle batter with oat mixture.
Bake at 400° for 15 to 20 minutes or until golden brown. Remove immediately from pans, and cool on wire racks.