Bring a large pot of salted water to a boil. While the water is heating, tear the bread into chunks (leaving on the crust is fine) and pulse in a food processor until it forms coarse crumbs.
Heat 2 Tbsp. of the olive oil in a large skillet. Add the crumbs and cook, stirring, over medium-low heat until they are toasted and crisp. Move the crumbs into a small bowl and return pan to the heat.
Add the pine nuts to the (empty) skillet and toast, stirring constantly, over low heat until golden. Be careful! They burn quickly. Add to the bowl with the toasted crumbs.
Add the remaining 4 Tbsp. oil and the garlic to the pan and return to the heat, cooking gently over low heat until the garlic begins to sizzle. Do NOT let the garlic brown. Add the figs and cook gently over low heat, turning carefully to coat them with the garlic oil, for about 2 minutes. The longer you cook them, the softer they will get, until they disintegrate (which is not what we're going for, here).
Sprinkle the fig mixture with the lemon zest, rosemary, salt and pepper. Stir gently, and keep warm.
Cook the fettuccine in the boiling water until al dente, about 3 to 5 minutes. Ladle out 1/3 cup cooking water and reserve. Drain the pasta and return to the pot.
Toss the cooked pasta with the lemon juice and half the reserved cooking water. Pour the fig mixture on top, add the bits of butter, and toss gently, over low heat, until the butter have melted and the pasta and figs are well-combined. Add more cooking water as necessary to keep the mixture moist (but not wet).
Transfer half the pasta mixture to a serving dish, and sprinkle half the toasted crumb mixture on top. Cover with the other half of the pasta mixture and top with the remaining crumbs.
Cover generously with Parmigiano-Reggiano and serve immediately.