Cinnamon Streusel Orange Muffins

I was craving muffins this morning and found this recipe on allrecipes.com. They are delicious......very moist with a hint of orange flavor. YUM!!

2 c. flour
3/4 c. sugar
2 t. baking powder
1/2 t. salt
1/3 c. veg. oil
1/2 c. orange juice
1/2 c. buttermilk (I used regular milk)
1 t. vanilla
2 eggs

3 T. brown sugar
1 1/2 t. cinnamon

1/4 c. flour
1/4 c. sugar
1 1/2 t. cinnamon
2 T. butter

Preheat oven to 350 degrees. Grease a 12 cup muffin tin. Stir together flour, sugar, baking powder, and salt. Make a well in the center of dry ingredients. Pour veg. oil, orange juice, milk, vanilla, and eggs into well. Slightly beat. Mix dry and wet ingredients together. It may be slightly lumpy. Fill muffin tins half way. Combine brown sugar and cinnamon and sprinkle evenly over muffin batter. Spoon remaining muffin batter over brown sugar mixture. Mix together remaining flour, sugar, cinnamon, and butter to make a crumbly mixture. Sprinkle this evenly over tops of muffin batter. Bake for 20 minutes.