In a large mixing bowl, combine 250 g all-purpose flour, 25 g sugar, and 7 g active dry yeast. Warm 90 ml milk until it's just lukewarm, then whisk in 1 egg and 30 g melted unsalted butter. Pour this mixture into your dry ingredients, and knead the dough for about 10 minutes until it becomes smooth and elastic. Allow the dough to rise in a warm place for about 1 hour or until it has doubled in size.

Once the dough has risen, punch it down gently and roll it out on a floured surface to about 1 cm thickness. Use a round cutter to cut out donut shapes, placing them on a parchment-lined baking sheet. Cover with a clean cloth and let the donuts rest for 30 minutes, allowing them to rise again and become fluffy before frying.

In a deep pan, heat oil to 170°C (340°F) for frying. Carefully add the donut shapes to the hot oil, avoiding crowding. Fry each donut for about 2-3 minutes on each side, or until they turn golden brown. When done, remove them from the oil and drain on paper towels to absorb excess oil, keeping them warm while you fry the remaining donuts.

While the donuts cool slightly, prepare the whipped cream filling. In a chilled bowl, pour in 300 ml heavy cream and optional 50 g condensed milk for sweetness. Using an electric mixer, whip the cream on medium speed until stiff peaks form, taking about 3-5 minutes. This velvety cream will bring richness to your Milk Cream Donuts.

Once the donuts have cooled, use a paring knife to make a small slit in each donut or use a piping bag. Fill each donut generously with the whipped cream mixture, ensuring they are packed with that delightful filling.

To finish off your Milk Cream Donuts, dust them lightly with 1 tablespoon of powdered sugar for an elegant touch. Serve warm or at room temperature, and enjoy the fluffy texture combined with the luscious cream filling.