Put yeast in the bowl of a stand mixer (or large mixing bowl) and pour 1 cup warm water (90° to 105°) on top. Let sit until yeast dissolves, 5 to 8 minutes.
Add milk, 1/4 cup oil, the kosher salt, and 1 tbsp. rosemary. Attach dough hook and with mixer on low, gradually blend in 6 cups flour. Beat on medium speed until dough is smooth and elastic, 10 to 12 minutes; if necessary, add about 2 tbsp. more flour until it's only slightly tacky. (Or knead by hand: Stir in 5 3/4 cups flour with a spoon, then knead on a work surface, adding flour as required to prevent sticking.)
Cover dough in bowl with a towel or plastic wrap and let rise at room temperature until doubled, 1 1/4 to 1 1/2 hours. Oil a 12- by 17-in. rimmed baking sheet with 1 tbsp. oil. Punch down dough, transfer to baking sheet, and use your hands to push it into an even layer; if it's too springy, let it rest about 10 minutes. Cover loosely and let rise until puffy, 45 to 60 minutes. Meanwhile, preheat oven to 425°.
With your fingers, poke holes 1 to 2 in. apart straight down into risen dough. Scatter blueberries over dough, then drizzle dough with 2 tbsp. oil. Combine remaining 1 tbsp. rosemary and the sugar; sprinkle on top.
Bake until golden, 25 to 30 minutes. Brush with remaining 2 tbsp. oil and sprinkle with flaked salt. Cool in pan on a rack 15 minutes. Loosen focaccia with a wide spatula and slide onto a work surface. Cut into pieces about 3 by 4 in. and serve warm or at room temperature.
All y'all guys be crazy. I've made this at least four times in the past year -- because my friends keep insisting I bring it to barbecues and potlucks. Maybe you're doing it wrong (looking at you, vpresser) or maybe you're just eating it for dessert for some crazy reason (looking at the rest of you reviewers), but this is an awesome recipe. Pretty easy, super impressive and absolutely delicious, especially as a side bread at a bbq or potluck. It's not dessert and it's not at all traditional focaccia -- it's blueberry rosemary focaccia and that's what it tastes like. And it's amazing.
The worst focaccia recipe ever! I have made many focaccia recipes. I thought it was weird that this recipe call for 6 cups of flour. I have never put that much flour into a focaccia. this focaccia was like a dry brick with no flavor, and I followed the recipe to the letter. it was so bad that I ended up throwing in the trash rather than serving to my family. One word to describe the recipe would by YUCK!!!!!!!!!!!!!!!!
The dough is delicious, but needs to be sweeter for this recipe. It just tastes like a good bread from the bakery with fruit and salt piled on top. The flavors don't meld. I liked the dough so I might try to tweak the recipe by sweetening the dough.