Make croutons and chop nuts
- Preheat oven to 400°. Place bread on one side of a rimmed baking sheet and walnuts on the other side (they cook at different rates). Drizzle bread with 3 Tbsp. oil; season with salt. Toss, squeezing bread with your hands to help it absorb as much oil as possible, until evenly coated. Bake until walnuts are golden brown and croutons are deeply browned and very crisp, 8–10 minutes for walnuts, 12–15 minutes for croutons. Let cool, then coarsely chop 1/2 cup of nuts.
- Meanwhile, combine 3 tbsp sherry/red wine vinegar, 1 garlic clove, and a bit of red pepper flakes in a medium bowl. Let sit 10 minutes to let garlic mellow and flavor the vinegar.
- Whisk 3 Tbsp. oil into vinegar mixture. Then add croutons and chopped nuts. Season with some salt.
- Use the whole fennel. Coarsely chop fronds, thinly slice stalks of fennel bulbs. Cut fennel bulbs in half and thinly slice. Add to dressing bowl.
- Add 3/4 cup torn mint leaves. Zest half lemon over salad, then squeeze in juice. Season with salt and toss to combine.
- Add dry croutons + nuts, then some Parmesan. When serving, top with more Parmesan and drizzle with oil.