Begin by preparing the focaccia bread dough. In a large mixing bowl, add the warm water, melted butter, and active dry yeast. Mix once or twice and then allow the mixture to sit for 5 minutes until the yeast is active. You will know it is active when it begins to foam.
Add the flour to the bowl and mix until a thick dough is formed. Cover the dough with a thin kitchen towel and allow it to sit in a warm place in your kitchen for one hour. It should double in size.
Remove the kitchen towel and transfer the dough into a well oiled metal pan. We used a 9x9 square pan. Oil the top of the dough and then use your hands to evenly distribute the dough in the pan so it touches all of the edges and corners. Let it rest and rise covered with a towel for another 15-30 minutes. Use your fingers to press down and create divots in the dough. Fold in the blueberries with your hands.
Preheat the oven to 350F. Bake the focaccia dough in the oven for 30 minutes. It will be golden brown on top when it's done.
While the focaccia is baking, prepare the icing by mixing the powdered sugar, cream cheese, and butter together until smooth and creamy.
Also, you may choose to top this with a blueberry syrup reduction. To prepare the reduction, bring a small saucepan with blueberries and agave to low heat. Cook 5 minutes, stirring, until the blueberries are bubbly and tender. Strain the blueberry pulp so that only the juice remains. Set aside to cool.
Remove the focaccia bread from the oven and drizzle with the cream cheese frosting. Top with more fresh blueberries or drizzle with blueberry syrup (or both). Enjoy warm!