Make the dough: in a large bowl combine the All-Purpose Flour and a pinch of the Sea Salt. Dissolve the Instant Yeast in lukewarm Water and let sit 5 minutes until foamy, then add to the flour along with a tablespoon of Olive Oil. Mix to form a shaggy dough, then turn out onto a lightly floured surface and knead 6–8 minutes until smooth and elastic.
First rise: shape the dough into a ball, coat lightly with oil, place in a bowl, cover and let rise in a warm spot until doubled, about 1 to 1½ hours.
Caramelize the onions: thinly slice the Yellow Onions. In a large skillet warm a couple tablespoons of olive oil over medium-low heat and add the onions. Cook slowly, stirring occasionally, until very soft and deep golden, about 30–40 minutes.
Season the onions: toward the end of cooking add minced Garlic, a few sprigs of Thyme (or a teaspoon dried), the Bay Leaf, and a generous grind of Black Pepper. Continue to cook 2–3 minutes to marry the flavors, then remove and discard the bay leaf and thyme stems if used.
Preheat oven to 425°F (220°C). Punch down the risen dough and roll or stretch it on a parchment-lined baking sheet into an oval or rectangle about ½" thick, leaving a slightly thicker edge.
Assemble the tart: spread the caramelized onions evenly over the dough, leaving a small border. Arrange Anchovy Fillets in neat lines or a lattice over the onions and scatter halved Black Olives across the top. Drizzle a little more olive oil over everything if desired.
Bake until the crust is golden and cooked through, about 18–25 minutes, rotating the sheet once for even color.
Finish and serve: remove from oven, let cool slightly, then slice and serve warm or at room temperature with an extra drizzle of olive oil and a final sprinkle of sea salt if needed.
