Combine whole wheat flour, all-purpose flour, 1/4 cup butter, 1 egg, sour cream, and 1/4 teaspoon salt in a bowl; knead until dough comes together. Shape dough into a ball. Wrap in plastic wrap and refrigerate until firm, at least 1 hour and up to overnight.

Roll out dough into a 10-inch circle on a lightly floured work surface.

Grease a 9-inch tart tin with 1 teaspoon butter. Press dough into the tart tin. Trim edges with a sharp knife. Place crust in the refrigerator.

Preheat oven to 350 degrees F (175 degrees C).

Heat olive oil in a large skillet over high heat. Add zucchini; cook and stir until just tender, 3 to 5 minutes. Season with thyme, salt, and pepper. Remove from heat.

Mix ricotta cheese and 1 egg together in a bowl. Fold in zucchini and Parmesan cheese gently.

Sprinkle bread crumbs over chilled crust; cover with prosciutto slices. Spread ricotta-zucchini mixture evenly over prosciutto. Smooth the top with a spatula; sprinkle pine nuts on top.

Bake in the preheated oven until center is firm and top is golden, about 35 minutes. Let stand for 10 minutes before slicing.