Prepare the Dough:

In a small bowl, dissolve the yeast in the lukewarm milk and let it sit for about 5 minutes, or until frothy.

In a large bowl, combine the sugar, eggs, butter, and vanilla extract. Mix in the yeast mixture.

Add the flour and salt, mixing until a soft and pliable dough forms.

Knead the dough on a floured surface for about 5-7 minutes, until it becomes smooth and elastic.

Place the dough in a greased bowl, cover with a clean cloth, and let it rise in a warm place for about 1 hour, or until doubled in size.

Prepare the Filling:

In a medium bowl, blend the cream cheese, sugar, and vanilla extract until smooth.

Mix in the finely chopped strawberries and set aside.

Shape and Fry the Doughnuts:

Punch down the risen dough and turn it out onto a floured surface.

Roll the dough to about 1/2 inch thickness.

Use a doughnut cutter or two round cutters (one larger and one smaller) to cut out doughnut shapes.

Heat oil in a deep fryer or large pot to 350°F (175°C).

Fry the doughnuts, a few at a time, for about 1-2 minutes per side, or until golden brown.

Transfer the fried doughnuts to a paper towel-lined plate to drain.

Stuff the Doughnuts:

Once the doughnuts have cooled slightly, use a piping bag with a small tip to fill each doughnut with the strawberry cheesecake filling.

Coat the Doughnuts:

In a small bowl, mix the granulated sugar and ground cinnamon.

Roll the filled doughnuts in the cinnamon sugar mixture until fully coated.