Preheat the oven to very hot (450 F) and roast the whole, unpeeled garlic heads on a dish in the oven. They should be very soft when fully cooked, which should take about 30 minutes.
Heat the chicken stock.
Use a separate pan to heat the olive oil, then add to it the shallots, garlic, and celery and sauté for about 5 minutes.
When the veggies have softened, add the Arborio rice and turn up the heat.
The rice will begin to fry, so stir frequently. In two minutes or so it will begin to appear slightly translucent. Add the wine and continue to stir.
Once the wine has cooked into the rice, start adding ladles of hot chicken stock and a pinch of salt. The ladles of stock should be added gradually, spacing them out as the rice soaks up the moisture.
Separate the roasted garlic cloves and squeeze out the soft insides into the risotto.
Add the thyme and pepper and turn the heat down to a simmer. Take care that the rice doesn't cook too quickly. Continue adding ladles of stock gradually.
Remove the risotto from the heat and add the butter and Parmesan. Stir gently. Place a lid on the pan and allow it to sit for a few minutes. This is an important part of making the risotto, as this is when it will become creamy and "oozy."
Add the remaining olive oil to a skillet with the almonds and breadcrumbs. Sauté until crisp and golden, and season with salt. Set to one side.
Serve the risotto with the toasted almonds and the breadcrumbs sprinkled over the top.