Preheat oven to 350 degrees and grease a 10x8-inch ovenproof baking dish with melted ghee or butter.
Scatter berries in the bottom of the dish. Slice strawberries in half, if needed.
In a small bowl, whisk together sugar, flour, and salt.
In a large bowl, whisk the eggs, then add flour-sugar mixture. Whisk in vanilla extract, then little by little, pour in milk while whisking to create a smooth batter. Pour batter over the berries and bake for 45 to 50 minutes. When the edges come away from the pan and the custard is cooked through, remove from oven and let cool. If desired, sift powdered sugar over top before serving.