1. Make the focaccia dough

In a large bowl, whisk together the warm water, instant yeast, honey, olive oil, and vanilla extract.

Add the bread flour and fine sea salt. Mix thoroughly until no dry patches remain and a shaggy, sticky dough forms.

Cover and let rest for 15 minutes.

Wet your hands and perform a series of stretch-and-folds. Grab one side of the dough, stretch it upward, then fold it over the center. Rotate the bowl and repeat until you've worked your way around the dough.

Cover and rest another 15 minutes, then repeat the stretch-and-fold process.

Cover and let proof at room temperature for 1 to 1½ hours, until nearly doubled, bubbly, and jiggly.

2. Fold the strawberry jam into the dough

Preheat the oven to 430°F with the rack positioned toward the bottom of the oven.

Line a 9 × 13-inch metal baking pan with parchment paper. Spread 3 tablespoons olive oil over the parchment and sides of the pan.

Gently transfer the dough to the prepared pan.

Spoon ½ cup of the strawberry jam filling over the dough and gently spread into a thin, even layer, leaving a small border around the edges.

Fold one side of the dough toward the center, then fold the opposite side over it, like folding a letter into thirds.

Rotate the dough so it runs lengthwise in the pan and carefully flip it seam-side down.

This creates ribbons of strawberry jam throughout the dough.

4. Second proof

Cover the pan and let the dough proof for another 1 to 1½ hours, until very puffy, bubbly, and jiggly.

Gently stretch the dough toward the edges of the pan if necessary.

5. Dimple and swirl

Spoon the remaining ¼ cup strawberry jam filling in small dollops across the surface of the dough.

Using lightly oiled fingertips, deeply dimple the dough, pressing almost all the way to the bottom of the pan.

As you dimple, gently push some of the strawberry jam into the pockets, creating swirls and little pockets of filling.

Avoid mixing the jam completely into the dough. You want distinct strawberry ribbons throughout.

6. Bake the focaccia

Bake for approximately 20–30 minutes, until the focaccia is golden brown, puffed, and cooked through in the center.

Start checking around 20 minutes. Because the strawberry jam contains sugar, the exposed pockets may caramelize more quickly. If the top begins to brown too much, loosely tent with aluminum foil.

Remove from the oven.

Allow the focaccia to cool for at least 30 minutes before glazing.

7. Make the strawberry donut glaze

In a medium bowl, whisk together the powdered sugar, freeze-dried strawberry powder, cooled strawberry purée, melted butter, vanilla extract, lemon juice, and salt.

Whisk until smooth, thick, and glossy.

The glaze should resemble classic strawberry donut frosting, thick enough to coat the focaccia without immediately running off.

If the glaze is too thin, add additional powdered sugar, 1 tablespoon at a time. If it's too thick, add whole milk a few drops at a time until spreadable.

8. Glaze and finish

Once the focaccia has cooled to room temperature, generously spread the strawberry glaze over the entire surface, allowing it to settle into the dimples and slightly drip down the sides.

Immediately scatter rainbow sprinkles over the glaze while it's still wet.

Let the glaze set for 15–20 minutes before slicing into squares and serving.