Preheat the oven to 475°F (246°C) with a rack in the center postion
Line a sheet pan with aluminum foil. Trim any dry, tough ends of the broccoli crowns, leaving roughly 2-inches of stalk attached. Slice the broccoli into ½-inch-thick steaks, starting in the center of each broccoli crown and working out to the edges, reserving any small or medium florets that fall off for roasting.
Whisk together the olive oil, grated or pressed garlic cloves, and red pepper flakes. Add the broccoli steaks and toss gently until evenly coated. Arrange the broccoli, cut-side down, on the lined sheet pan, setting them apart slightly. Sprinkle with salt.
Roast the broccoli for 10 to 12 minutes. Remove the pan from the oven, flip the broccoli, and sprinkle the almond slices evenly across the sheet pan. Roast for an additional 8 to 10 minutes
Transfer the broccoli to a platter, toss gently with the lemon juice and top with the grated pecorino cheese. Garnish with fresh lemon zest.