This isn't really summery but it is a good treat. For me, it satisfies the craving for cinnamon rolls with way less work and way less fat. I've included my own little changes in parentheses to make it even healthier.
2 c. flour (I use 1 cup whole wheat)
4 tsp baking powder
1 1/4 tsp salt
1/3 c. oil (you can use applesauce for all or part of this)
1 c. sugar (you can substitute in some applesauce here too)
1 1/2 tsp cinnamon
1 c. buttermilk (I often use regular milk or plain yogurt instead)
2 tsp vanilla
Preheat oven to 350. Grease and flour bottom of a 9x5 loaf pan. Combine all ingredients and beat 3 minutes at medium speed. Pour half of the batter into the pan. Prepare streusel topping (Combine 1/2 c. brown sugar, 1 tsp cinnamon, 2 T. softened butter) and sprinkle half over the batter. Pour on the rest of the batter and top with remaining topping. Bake for about 45 minutes.