Bloom the yeast (if using active dry): In a small bowl, mix warm water with 1 tsp sugar and yeast. Let it sit 5–10 minutes until foamy. If using instant yeast, skip this step and add it directly to the flour.

Mix the dough: In a large bowl, whisk flour, sugar, and salt. Add warm water, yeast (bloomed or instant), 1/4 cup olive oil, lemon zest, and optional vanilla. Stir with a spoon until a shaggy dough forms.

Knead briefly: Turn the dough onto a lightly oiled surface and knead 2–3 minutes until smooth-ish and tacky. It should be soft and slightly sticky.

First rise: Oil a clean bowl, add the dough, and turn to coat. Cover and let rise at room temperature until doubled, about 60–90 minutes.

Pan and rest: Generously oil a 9x13-inch pan (or a large sheet pan for thinner focaccia). Gently stretch the dough to fit. If it springs back, rest 10 minutes, then finish stretching.

Dimple and top: Drizzle 1–2 tbsp olive oil over the dough. With oiled fingers, press deep dimples all over. Scatter blueberries evenly, pressing some lightly into the dough. Sprinkle with a pinch of flaky sea salt and, if using, fresh thyme.

Second rise: Let the topped dough rest 20–30 minutes until puffy. Meanwhile, preheat the oven to 425°F (220°C).

Bake: Bake 20–25 minutes, until golden at the edges and lightly browned on top. If berries release lots of juice, that’s fine—those spots will be jammy.

Finish with lemon-honey glaze: In a small bowl, whisk honey with lemon juice. While the focaccia is warm, brush or drizzle the glaze over the top. Add a final swirl of olive oil and a few pinches of flaky salt.

Cool and slice: Let it rest 10–15 minutes before cutting into squares or strips.