Preheat your oven to 375°F and grease a 9-inch baking dish or cast iron skillet with that 2 tablespoons of melted butter. Make sure the entire bottom and sides get coated—this prevents sticking and creates those golden, crispy edges. Don't skip this part; it genuinely makes the difference.

Combine flour, sugar, salt, and vanilla in a large mixing bowl. Whisk them together until everything's evenly distributed, breaking up any sugar lumps you find. The mixture should look uniform with no little clumps hiding.

Pour in your eggs and milk, then whisk everything together until you get a smooth batter. It'll look like pancake batter—kinda thin but not watery. I usually whisk for about 1 minute until there are no flour streaks, then stop (overmixing makes it tough).

Scatter your sliced strawberries and blueberries evenly across the bottom of your prepared baking dish. Don't crowd them—you want the batter to flow around each berry so the strawberry blueberry clafoutis cozy rises properly. I usually toss them around with my hands to space them out.

Pour that smooth batter over the berries, letting it settle around them naturally. The fruit won't sink if you don't stir it—just let gravity do the work. Some berries might float a little, and that's totally fine.

Bake for 35-40 minutes until the top turns golden brown and a toothpick inserted in the center comes out clean. Around minute 30, take a peek—it should be puffing up and looking amazing. Mine always sticks a little to the pan edges, and honestly, that's how you know it's crispy.

Let it cool for 5 minutes on the counter, then dust with powdered sugar if you're feeling fancy. Serve it warm, ideally with whipped cream or vanilla ice cream on the side.