Weigh the ingredients, then simply stir together. Remove the dough to a well-floured work surface. Move the dough through the flour to remove any stickiness.
Place the dough in a bowl with the olive oil. Do a series of stretch and folds over 90 minutes. Finally, shape the focaccia, add your toppings, then let rise briefly before baking.
I've used canned cherry tomatoes here, but fresh grape or cherry tomatoes are also a good option.
Use raw red onion or caramelized onions.
Try thin slices of apple or pear. Great with some cheese and/or nuts, too.
Parmesan, cheddar, blue, feat or goat cheese are good options.