To the bowl of a slow cooker, add the butter, onions, thyme, salt and pepper. Let cook on high for 4 hours, uncover and then cook an additional 2-3 hours until all the liquid has evaporated.
Preheat the oven to 350F.
Once the onions are done, to a small (approx 6") cast iron skillet or other oven safe pan over med-high heat, add 1/2 TB oil and rice. Let cook about 2 minutes. Add the wine and broth and bring to a boil. Stir in the onions and cheese. Cover with a lid or foil.
Bake approximately 25 minutes until all the liquid has been absorbed.
While the risotto is baking, to a small pan over medium heat, add the remaining oil and breadcrumbs. Toast, stirring occasionally until the breadcrumbs are golden brown.
Once the risotto is done, cover with the breadcrumbs and serve immediately.