Preheat oven to 350 degrees F.
In a stand mixer bowl, add the warm water, yeast, and sugar. Allow to sit for about 5 minutes, or until bubbly.
Add the avocado oil and about 3½ cups of Einkorn flour and mix on low for about 2 minutes. Add the last cup of flour about ¼ cup at a time, just until the dough pulls away from the sides of the bowl and isn't sticky (you want to add enough flour so your dough is firm enough to hold a shape but still soft).
Gently place a kitchen towel or plastic wrap over the dough and let it rise for about 10 minutes.
Transfer the dough to a lightly floured surface and roll out into a rectangle that is about ⅓"-½" thick. Brush with melted butter, then sprinkle the brown sugar and cinnamon over the top.
Cut into 1" strips and twist the breadsticks. Lay on a greased cookie sheet, then sprinkle again with ground cinnamon.
Let sit for 10 more minutes or until double. (**Hack--put the baking sheet with the breadsticks in the oven for a minute to warm the pan up. Take the pan back out of the oven and continue to rise. It will help your breadsticks rise twice as fast if your pan is warm.)
Bake in the preheated oven for about 15-18 minutes, or until golden.
While the Einkorn Cinnamon Breadsticks are baking, combine the powdered sugar, milk, and vanilla in a small bowl.
Once the breadsticks have baked, remove from the oven and let cool for 5 minutes. Drizzle the glaze over the breadsticks.
Serve immediately or store in a freezer bag or another airtight container. Enjoy!