Preparation Melt butter in heavy medium saucepan over medium heat. Add garlic; sauté until fragrant, about 1 minute. Add flour; stir 3 minutes. Whisk in hot milk. Bring to simmer, stirring. Cover partially; simmer until sauce thickens slightly, stirring occasionally, about 8 minutes. Remove from heat. Add cheddar and Jack cheese, 1 1/3 cups Parmesan cheese and hot pepper sauce. Whisk until sauce is smooth. Season with salt and pepper. (Can be made 1 day ahead. Cover; chill. Whisk over medium heat to rewarm before using.) Preheat oven to 400°F. Generously butter bottom and sides of 13x9x2-inch baking dish. Blend 1/3 cup Parmesan, almonds and breadcrumbs in processor until nuts are coarsely ground. Add 1/2 cup almond mixture to prepared dish. Tilt dish to coat bottom and sides. Return any loose almond mixture to processor. Cook pasta in large pot of boiling salted water until tender. Drain well. Return pasta to pot. Add sauce; stir to coat. Transfer to prepared dish. Sprinkle remaining almond mixture over. Bake until almond mixture is golden and crunchy and sauce bubbles, about 30 minutes. Cool on rack 5 minutes.
Preparation Melt butter in heavy medium saucepan over medium heat. Add garlic; sauté until fragrant, about 1 minute. Add flour; stir 3 minutes. Whisk in hot milk. Bring to simmer, stirring. Cover partially; simmer until sauce thickens slightly, stirring occasionally, about 8 minutes. Remove from heat. Add cheddar and Jack cheese, 1 1/3 cups Parmesan cheese and hot pepper sauce. Whisk until sauce is smooth. Season with salt and pepper. (Can be made 1 day ahead. Cover; chill. Whisk over medium heat to rewarm before using.) Preheat oven to 400°F. Generously butter bottom and sides of 13x9x2-inch baking dish. Blend 1/3 cup Parmesan, almonds and breadcrumbs in processor until nuts are coarsely ground. Add 1/2 cup almond mixture to prepared dish. Tilt dish to coat bottom and sides. Return any loose almond mixture to processor. Cook pasta in large pot of boiling salted water until tender. Drain well. Return pasta to pot. Add sauce; stir to coat. Transfer to prepared dish. Sprinkle remaining almond mixture over. Bake until almond mixture is golden and crunchy and sauce bubbles, about 30 minutes. Cool on rack 5 minutes.