Mix the yeast with warm water in a bowl.

In the bowl of a stand mixer fitted with a dough hook, combine the flour, milk, butter, egg yolks, and sugar with the yeast mixture. Blend on low speed until a dough ball forms and pulls away from the sides of the bowl.

Turn the dough out onto a floured surface and knead until smooth.

Place the dough in a large bowl lightly greased with olive oil. Cover with a towel and let it rise until doubled, about 90 minutes.

Punch down the dough and divide it into 14 pieces.

Shape the pieces into small balls and place them on a baking tray lined with flour-dusted parchment paper. Cover and let them rise again for about 30 minutes.

Heat the oil to 375°F.

Fry 3-4 donuts at a time in the hot oil, cooking each side for 1-2 minutes. Remove and drain on paper towels.

Once drained, coat the donuts in sugar and create a hole in the side of each using a sharp tool.

In the stand mixer, combine cream cheese, powdered sugar, and strawberry preserves.

Simmer the strawberries, granulated sugar, and water in a small pan for about 10 minutes. Let cool.

Stir 1 cup of the strawberry mixture into the cream cheese filling.

Fill a piping bag with the cream filling. Pipe the filling into each donut until filled.