Step 1

For the dough, in a food processor, combine both flours with the salt and pulse to mix

Step 2

Add the butter and pulse until pea-size pieces form

Step 3

Add the sour cream, ice water and lemon juice and pulse until the dough starts to come together

Step 4

Transfer to a lightly floured work surface, gather any crumbs and knead until smooth

Step 5

Pat into a disk, wrap in plastic and refrigerate until chilled, about 1 hour

Step 6

Preheat the oven to 400°F

Step 7

Line a baking sheet with parchment paper

Step 8

For the filling, in a small bowl, toss the fennel with 1 tablespoon of the olive oil and season with salt and pepper

Step 9

In a medium skillet, heat another tablespoon of olive oil

Step 10

Add the shallot, season with salt and cook over moderately low heat, stirring, until softened and lightly browned, about 6 minutes

Step 11

Remove the shallot to a small bowl and allow to cool

Step 12

In the same skillet, add the fennel and cook until slightly softened and golden brown, about 3 minutes per side

Step 13

Set aside

Step 14

In a small bowl, mix the ricotta with the lemon zest, garlic, 1 teaspoon thyme, 1 teaspoon minced oregano and ½ teaspoon minced rosemary

Step 15

Season with salt and pepper

Step 16

In a large bowl, toss the squash with the celery root and the remaining 1 tablespoon olive oil

Step 17

Season with salt and pepper

Step 18

On a lightly floured work surface, roll out the dough to 
a 13-inch round

Step 19

Transfer to the prepared baking sheet

Step 20

Spread the ricotta mixture on the dough, leaving a 1-inch border

Step 21

Pile the squash mixture on the ricotta, then scatter the caramelized fennel on top and top with the shallots

Step 22

Fold 1 ½ inches of the dough edge over the vegetables

Step 23

Sprinkle with more thyme, oregano and rosemary leaves

Step 24

Brush the dough edge with the beaten egg

Step 25

Bake the crostada for 15 minutes, until it starts to brown

Step 26

Sprinkle the Parmigiano over the filling and bake 15 to 20 minutes more, until the vegetables are tender and the crust is golden

Step 27

In a small bowl, mix the honey with the lemon juice and red pepper flakes (if using)

Step 28

Drizzle the honey mixture over the crostada just before serving