Slow Cooker Quinoa Breakfast Casserole with Tomato and Spinach

quinoa (rinsed well and uncooked)

milk (I used 2%)

large eggs

salt

pepper

frozen cut leaf spinach (or use a handful of fresh!)

grape tomatoes (halved)

shredded cheese (colby, monterey jack, cheddar, etc.)

shredded Parmesan cheese