To the bowl of a stand mixer fitted with the dough hook(you can also make this in a bowl with a spatula), add yeast, warm water, and olive oil. Let sit until frothy and bubbly, 5-8 minutes.
Add flour and salt, and mix on medium speed for 5 minutes, or knead by hand until the dough is smooth. Cover with plastic wrap and let rise for one hour to 90 minutes, until doubled in size.
Sweet Roasted Peppers
While the dough is rising, prepare the peppers. Heat the oven to 220C/ 420 F on the grill setting.
Place the peppers on a baking sheet or in a baking dish and char for 15 to 20 minutes, turning once you see the skin on the top turn black. Use kitchen tongs to move the peppers directly from the oven to a clean plastic bag, and tie off the top. Let the peppers steam and cool off. Once cool, cut the peppers in half and scrape off the burnt black skin with a knife(discard the charred bits).
Slice the red flesh into thin strips. Add the olive oil to a small saucepan and add in the peppers. Let the liquid from the peppers cook off for about 2 minutes and then add the sugar, vinegar, coriander seeds. Cook until the texture thickens to that of marmalade(around 5-7 minutes). Season with salt. Set aside.
Bake
Preheat the oven to 200C/400F with baking steel or pizza stone/baking sheet inside.Divide the dough in half and roll out each half to an oval shape about a hand and a half in length.Carefully place the focaccias on the hot baking sheet. Top each with an even amount of red pepper marmalade.Bake till golden, 10-12 minutes. Remove from the oven.Combine the finishing olive oil, salt, and thyme in a small bowl.Use a pastry brush to brush edges of focacca with finishing oil. Slice and serve warm!