Clean the lemon well, and then remove the zest using a fine cheese grater or zester. In a large bowl, combine the lemon zest, juice from half the lemon, eggs, milk, yogurt, sugar, vanilla extract, salt, and baking soda. Whisk until smooth.
Stir in the raspberries (thawed), and then stir the oats. Coat a casserole dish with non-stick spray and pour in the oat mixture.
Place the dish in a preheated 375 degree oven and bake for about 45 minutes or until the center is no longer liquid. Serve hot.