Heat the olive oil over high heat in a large pan. Add the rapini and quickly sauté – I like to get a little bit of color on the rapini. Once it starts to wilt, about 2 minutes, toss in the garlic, horseradish, chili flakes and almonds and season with salt and pepper. Continue cooking for 2 more minutes, then remove to a large serving platter. Sprinkle with the diced quince paste, give it a drizzle of lemon juice and serve right away.