In small bowl dissolve yeast in warm water. Let sit until foamy, about 5 to 10 minutes. Place yeast and water in mixer bowl add olive oil, butter, milk and minced rosemary. Slowly start adding flour while mixing on low speed. Continue adding flour until dough comes together. Dough will be somewhat soft, do not add more flour than necessary to handle. Knead dough for 5 to 10 minutes until soft and smooth. Place back into mixer bowl and cover with towel. Set in warm place to rise for about 1 to 2 hours, until doubled. Punch down dough, and then divide into 12 equal pieces. Shape into flat balls and re-cover with towel. Let sit 10 to 15 minutes. Shape dough by stretching and flattening into a 5-inch disk. Place on cookie sheet lightly sprinkled with semolina flour. Cover with towel while you shape remaining loaves. Using your fingertips, poke many small holes into each focaccia. Re-cover with towel and let rise for an hour until doubled in size. Poke each loaf again with your fingertips, and then arrange the roma tomato slices in a circle on top. Drizzle the loaves with 1/4 cup of olive oil, sprinkle with kosher salt and rosemary leaves. Bake at 425 degrees for 20 to 30 minutes until golden brown. Brush loaves with olive oil, remove from sheet, and cool on racks.