In a large bowl, stir together warm milk, yeast, and 2 teaspoons sugar. Let stand until mixture is foamy, about 5 minutes. Stir in butter, vanilla, salt, eggs, and remaining ⅔ cup sugar. Gradually add 3 cups flour, beating with a mixer at medium speed until combined. Stir in strawberries and enough flour until mixture begins to pull away from sides of bowl (about 2½ cups).
On a lightly floured surface, turn out dough. Knead until smooth and elastic, about 8 minutes, using enough remaining flour (about 2 teaspoons at a time) to prevent dough from sticking to hands. Spray a large bowl with cooking spray. Place dough in bowl, turning to grease top. Cover and let stand in a warm, draft-free place (75°) until doubled in size, about 1 hour and 15 minutes.
Punch dough down. Cover and let stand for 5 minutes. On a lightly floured surface, roll dough ½-inch thick. Using a 3-inch doughnut cutter dipped in flour, cut dough, rerolling scraps as necessary. Reserve doughnut holes. Place dough on lightly floured baking sheets. Cover and let rise in a warm, draft-free place (75°) until doubled in size, about 40 minutes.
Fill a large cast-iron Dutch oven halfway full with oil, and heat over medium heat until a deep-fry thermometer registers 350°. Gently remove doughnuts from baking sheets; fry in batches until golden brown, about 1½ minutes per side. Fry doughnut holes until golden brown, about 1 minute. Let drain on several layers of paper towels. Let cool to room temperature.
Dip doughnuts in Strawberry Glaze; let stand for 5 minutes. Dip in glaze again. Garnish with crushed strawberries, if desired. Let stand on a wire rack until glaze is set.
Recipe by Taste of the South at https://tasteofthesouthmagazine.com/strawberry-doughnuts/