Gather these ingredients to make these donuts:
-Bread flour
-Large egg
-Instant yeast
-White granulated sugar
-Unsalted butter
-Warm milk
-Table salt
For the custard:
-Diced strawberries
-Unsalted butter
-Vanilla extract
-White granulated sugar
-Heavy cream
-Cornstarch
-Water
-Sea salt
-Egg yolks