Warm the liquid: In a small saucepan or microwave, warm 1 cup milk or oat milk until it’s warm to the touch (100–110°F), not hot. Stir in 1 tablespoon granulated sugar and the yeast.
Let sit 5–10 minutes until foamy.
Mix the dry base: In a large bowl, whisk 2 1/2 cups all-purpose flour, 1/2 cup oat flour, and 1 teaspoon salt. Keep the remaining all-purpose flour nearby to adjust the dough as needed.
Combine wet ingredients: In another bowl, whisk 2 eggs, 1 teaspoon vanilla, and 4 tablespoons softened oat butter until smooth.
Make the dough: Pour the yeast mixture and the egg mixture into the dry ingredients. Stir with a wooden spoon or use a mixer with a dough hook until a shaggy dough forms.
Add more all-purpose flour, a few tablespoons at a time, until the dough is soft and slightly tacky but not sticky.
Knead: Knead on a lightly floured surface (or with a mixer) for 6–8 minutes. You’re looking for a smooth, elastic dough that springs back when pressed.
First rise: Place dough in a lightly greased bowl, cover, and let rise in a warm spot until doubled, about 60–90 minutes.
Make the filling: In a small bowl, mix 1/2 cup brown sugar, 2–3 teaspoons cinnamon, and a pinch of salt. Have 4 tablespoons softened oat butter ready.
Roll it out: Punch down the dough and roll it into a 12x16-inch rectangle.
Spread the softened oat butter evenly over the surface, then sprinkle the cinnamon-sugar mix evenly. Add optional nuts or raisins if you like.
Shape the rolls: Starting from a long side, roll the dough into a tight log. Trim the ends if needed.
Slice into 12 even pieces using unflavored dental floss or a sharp knife.
Second rise: Arrange rolls in a greased 9x13-inch pan with a little space between them. Cover and let rise until puffy, 30–45 minutes.
Bake: Preheat oven to 350°F (175°C). Bake 20–24 minutes until lightly golden and set in the center.
Don’t overbake—soft is key.
Glaze: Whisk 1 cup powdered sugar, 1–2 tablespoons milk or oat milk, and 1/2 teaspoon vanilla until smooth and pourable. Drizzle over warm rolls. For a richer frosting, add 2 tablespoons softened oat butter for a creamy finish.