Gluten Free Potato Kugel Gratin

Name: Gluten Free Potato Kugel Gratin
Ingredients: 5-6 gluten free matzo crackers or 1 cup gluten free matzo meal; 1/2 cup extra-virgin olive oil; 3 1/2 lbs russet potatoes, peeled (about 6 large); 9 oz thinly sliced shallots, (about 5 medium sized); 1 1/2 tbsp minced fresh rosemary, plus an additional 1/2 tbsp, chopped for garnish; 1 1/2 tbsp minced fresh thyme, plus an additional 1/2 tbsp, chopped for garnish; 4 large eggs, at room temperature; 1 cup vegan chicken broth or regular chicken broth; kosher salt; fresh ground pepper; flaky sea salt, garnish