In a small cazuela or terra-cotta casserole, lay half the remaining peppers in a single layer, taking care not to overlap the peppers. Spoon half of the pepper puree on top of the peppers and smooth it out with the back of the spoon. Split open the garlic cloves by placing them on a chopping board and pressing down hard with the base of your hand or the flat side of a paring knife. Scatter the garlic over the puree and season to taste with salt. Make another layer of peppers, cover with the remaining puree and season again with salt.
Cover the peppers with one cup of the olive oil. Bake in the oven for 1 1/2 hours, until the peppers are completely tender. Remove from the oven, set aside and keep warm.
Increase the oven to 450 degrees. Heat the remaining 2 teaspoons of olive oil in an ovenproof sauté pan over high heat. When the pan begins to slightly smoke, add the sirloins and sear on all sides, about 2 minutes per side. Transfer the pan with the sirloins to the oven and roast for 6 to 8 minutes or until the sirloins reach 130 degrees on a meat thermometer (for medium rare). Transfer the sirloins to chopping board and let rest for 5 minutes.
To serve, spread the peppers and puree on a serving tray. Slice the sirloins into 1/2-inch thick slices and place them on top of the peppers. Drizzle the medallions with extra olive oil from the peppers and sprinkle with salt.