Step 1: Make the Dough
In a large bowl, mix Bisquick, sugar, egg, and milk until a soft dough forms.
If dough is too dry, add 1 tbsp more milk at a time until it comes together smoothly.

Step 2: Roll & Cut
Lightly flour a surface and roll out the dough to about ½ inch thickness.
Use a donut cutter or two different-sized round cutters to form donuts.
Gather scraps, re-roll, and cut again until all dough is used.

Step 3: Heat Oil
In a deep pan, heat about 2 inches of vegetable oil to 350°F (175°C).
Test with a thermometer or drop a small piece of dough in—it should sizzle and rise quickly.

Step 4: Fry the Donuts
Carefully add donuts (2–3 at a time) into the hot oil. Fry for 1–2 minutes per side until golden brown.
Use a slotted spoon or tongs to remove and drain on paper towels.

Step 5: Add Toppings
While still warm, toss donuts in cinnamon sugar or dust with powdered sugar.
Let cool slightly before dipping in glaze or frosting, then add sprinkles if desired.