This is the best focaccia recipe I've found; and its easier to make, than you think. Just stir together the dough in your mixer, refrigerate overnight, bake in the morning. Add rosemary and stuff if you want. I usually keep it simple with just some flaky salt so I can split it, toast it and spread with honey for breakfast.
Mr. Reinhart's recipe calls for bread flour, but I prefer unbleached all-purpose flour.
Focaccia
by Peter Reinhart
5-1/2 cups all-purpose flour (1 lb. 9 oz.)
2 tablespoons + 1 tsp. granulated sugar (1 oz.)
2 teaspoons table salt or 4 teaspoons kosher salt
1 package (2-1/4 tsp.) instant yeast
2 1/2 cups cold water
8 tablespoons olive oil divided
coarse sea salt (like Maldon)
1. Combine the flour, sugar, salt, yeast and water in the large bowl of a stand mixer. Using the paddle attachment, slowly mix until the ingredients form a ball around the paddle, about 30 seconds. Switch to the dough hook and mix on medium low for another 3 minutes. Stop the machine. Scrape the dough off the hook; let the dough rest for 5 minutes and then mix on medium low for another 3 minutes, until relatively smooth. The dough will be very wet and sticky.

2. Coat a bowl large enough to hold the dough when it doubles in size, with 1 tablespoon of olive oil. Transfer the dough to the bowl and rotate the dough to coat it with oil.

3. Hold the bowl steady with one hand. Wet the other hand with water. Grasp the dough and stretch it to nearly twice its size. Lay the stretched section back over the dough. Rotate the bowl 1/4 turn. Repeat rotating and stretching the dough four times. Drizzle 1 tablespoon of oil over the dough and flip it over. Wrap the dough well with plastic and let dough rise until doubled. You may refrigerate overnight for a slow rise.

4. Cover a 13x18-inch rimmed baking sheet with parchment or a silicone baking mat and coat the surface with 2 tablespoons olive oil. Gently slide a rubber spatula or dough scraper under the dough and guide it out of the bowl, onto the center of the pan. Drizzle 2 tablespoons olive oil on top of the dough. Using your fingertips (straight up and down), dimple entire surface of dough while gently pushing dough down and out toward edges of pan. Don't be concerned if dough won't reach corners. If dough resists, let it rest for 20 minutes, then continue to dimple and stretch.

5. Preheat oven to 475°. Put the pan on a rack to let air circulate around it. Don't cover the dough with anything, just be sure the surface of the dough is coated with enough olive oil to prevent it from drying out as it rises to about 1-1/2 times its original size and swells to the rim of the pan.

6. Just before baking, sprinkle some sea salt over the dough. Put pan in the middle of the oven and reduce heat to 450°. Bake 15 to 20 minutes, until golden brown on top and bottom. Remove focaccia from pan and parchment and set on rack to cool.