Begin by finely dicing your fresh strawberries and mixing them gently with a tablespoon of granulated sugar. Let this mixture sit for about 10 minutes to allow the strawberries to macerate.

In a medium saucepan, combine heavy cream, whole milk, and a pinch of fine sea salt over medium heat. Cook gently until it starts to simmer, but don’t let it boil.

In a separate bowl, whisk together the egg yolks and sugar until pale and thickened. Gradually add the warm cream mixture to the egg mixture, then return the combo to the saucepan. Cook on low heat, stirring constantly, until the custard thickens—about 5 minutes. Add butter, vanilla extract, and the macerated strawberries before chilling the custard for at least an hour.

In a bowl, heat warm milk (around 110°F) to activate the active dry yeast. Once it’s warm, sprinkle the yeast over the milk and let it bloom for about 5-10 minutes until it's bubbly.

In a larger mixing bowl, combine melted butter, sugar, and eggs with the bloomed yeast. Gradually mix in all-purpose flour and a dash of salt until a smooth dough forms, then turn it out onto a floured surface to knead for about 8-10 minutes until elastic.

Transfer the kneaded dough into a greased bowl and cover it with a clean kitchen towel. Let the dough rise in a warm spot for about 2 hours or until it has doubled in size.

After the dough has risen, roll it out on a lightly floured surface to about ½-inch thick. Use a doughnut cutter or two round cutters to shape your doughnuts, making sure to create a hole in the middle.

In a deep skillet or fryer, heat vegetable oil to 375°F for frying. Once hot, carefully drop the doughnuts into the oil, frying them for approximately 1 minute on each side or until they turn golden brown.

While the donuts are still warm, coat them in granulated sugar for a sweet finish. Once cooled, use a piping bag fitted with a thin tip to fill each doughnut generously with the chilled strawberry custard.