In a large bowl, whisk together the flour, instant yeast, and salt. Gradually add the warm water and 1/4 cup olive oil, mixing until a shaggy dough forms. Turn the dough out onto a lightly floured surface and knead for 8-10 minutes until smooth and elastic. Alternatively, use a stand mixer with a dough hook for 6-8 minutes.

Lightly grease a clean bowl with olive oil. Place the dough in the bowl, turning to coat. Cover with plastic wrap and let rise in a warm place for 1 to 1.5 hours, or until doubled in size.

While the dough is rising, prepare the topping. In a small bowl, combine the sliced garlic scapes, spring onions, 3 tablespoons of olive oil, salt, and pepper. Set aside.

Preheat your oven to 425°F (220°C). Grease a 9x13 inch baking pan generously with olive oil. Punch down the risen dough and gently press it into the prepared baking pan, stretching it to fill the corners. If the dough resists, let it rest for 5-10 minutes before continuing.

Dimple the surface of the dough all over with your fingertips. Evenly distribute the garlic scape and spring onion mixture over the dough, pressing it lightly into the surface.

Bake for 20-25 minutes, or until the focaccia is golden brown and cooked through. Let cool in the pan for a few minutes before transferring to a wire rack. Serve warm or at room temperature.