In the bowl of a stand mixer, add 1 cup warm water, yeast and sugar. Mix lightly with a fork to get all the yeast in the water and set aside for about 15 minutes. It should begin to foam up and you should see little bubbles.
In another bowl, whisk together the oil, honey and 2 eggs and pour mixture into the yeast mixture.
Using a dough attachment on your mixer on low-medium speed, gradually add the flour, salt, garlic powder and chopped rosemary, about 1/2 cup of flour at a time with the mixer on low. Continue to mix until everything is incorporated. The dough should begin to pull away from the bowl and come to 1 large ball of dough.
Turn the dough onto a very well floured surface and knead for about 5 minutes. You can use your finger to see if it's ready. Press your finger in and if the dough bounces back quickly, it's ready.
In a large bowl, pour a bit of oil in and place your dough ball in the bowl. Turn it around so the entire dough is covered with a thin layer of oil. Cover with a clean towel and place bowl in a warm spot. (for me, it was my oven). Allow to rest and rise for 1 1/2 hours until doubled in size.
When dough is ready, it should have doubled in size. Punch the dough down and divide dough into 2 balls, this will be your challahs. Cover 1 ball of dough as you work with the other.
Divide dough into 3 or 4 pieces (depending on what kind of braid you'd like), which will be your strands. Roll each strand into a long rope all of equal sizes, about 8-10 inches in length and continue with desired braid.
Pre-heat oven to 350 degrees Fahrenheit and place challahs on baking sheet. Brush each challah with egg wash and sprinkle with course sea salt and chopped rosemary and place sliced garlic in the "nooks" of the braid. Allow to rest for another 30 minutes.
Bake challah for about 30 minutes or runtil the top is lightly golden brown.