In the bowl of a stand mixer, add yeast and warm water. Let stand for 10 minutes. Add sugar, salt, unsalted butter, egg, egg yolk, vanilla extract, and almond extract. Attach the dough hook and mix on low speed to combine.
Add 2½ cups flour, half a cup at a time while the stand mixer is on low speed. Knead on low until the dough starts to form. If the dough is still very sticky add more flour, 1 tablespoon at a time until the dough pulls away from the sides of the bowl. The dough should be somewhat tacky, but not sticky.
Transfer the dough to a lightly greased bowl and cover it tightly with plastic wrap. Make sure to place the bowl in a draft free, warm spot in your kitchen. Allow it to rise for 2 hours.
Gently press in the middle of the dough to deflate. Wrap the dough in plastic wrap and refrigerate for 6 to 8 hours, or overnight.
On a lightly floured surface, roll the dough out to about ½ inch thick. Use a round donut cutter or a large round cookie cutter to cut circles out of the dough. Use a smaller round cutter or something about 1 inch across that is round to cut out the center of the donut (donut holes). Place the cut-out donuts and donut holes on a parchment-lined baking sheet. Lightly cover with plastic wrap, and then drape a clean dry towel over the top and allow to rest for 1 hour (no more than 1 hour or the dough will start to get too yeasty).
In a large Dutch oven filled with 2 to 3 inches of vegetable oil over medium heat, bring the temperature of the oil up to 350°F. Use a thermometer to test the temperature. Having the temperature hotter than 350°F will cook the donuts too quickly and the inside will still be doughy. Carefully place the donuts into the hot oil and allow to cook on each side until golden brown. Work in batches so you don’t overcrowd the pot.
Carefully remove the cooked donuts and place them on a baking sheet lined with paper towels and a cooling rack. Repeat the steps until all of the donuts have been cooked.
Glaze
In a separate mixing bowl combine powdered sugar, milk, vanilla extract, and butter extract. Use a whisk to combine until no lumps remain. Carefully lower each slightly cooled donut (one at a time) into the glaze. Gently flip the donut to coat the other side. Return the donuts back to the cooling rack and allow the glaze to set, for about 10 minutes.