Whisk together flour, ½ tsp. salt and baking powder in a medium bowl. Using a pastry blender, cut in butter until pieces are pea size. Stir in yogurt and 1 Tbsp. milk. Stir in enough of the additional milk, 1 Tbsp. at a time, until dough holds together. Gather dough and press together to form a ball; knead 5 to 10 times or until no longer crumbly. Shape into a 1-in.-thick disk. Wrap in plastic wrap; refrigerate for 30 minutes or up to 2 days.

Preheat oven to 425°. Roll dough between 2 sheets of parchment paper into a 13-in. round. Remove parchment paper. Ease pastry into a 9½-in. deep-dish pie plate. Trim pastry ½-in. beyond the edge of the pie plate; fold under pastry even with pie plate edge. Crimp edge as desired. Prick entire bottom and side of pastry shell with a fork. Bake for 13 minutes or until partially set. Cool completely. Cover and refrigerate up to 12 hours.

Cut asparagus into 7 (3-in.) spears; set aside. Cut remaining asparagus into thin ribbons using a vegetable peeler. Cut carrots lengthwise using a julienne peeler; then cut julienne strips crosswise into 2- to 3-in.-long pieces.

Fill a large saucepan with water; bring to a boil. Add asparagus spears and ribbons, carrots and sugar snap peas; cook for 1 minute. Drain. Quickly chill in ice water; drain again and return to bowl. Cover and refrigerate up to 12 hours.

For filling, whisk together eggs, half & half, mustard, ½ tsp. salt and ¼ tsp. pepper. Cover and refrigerate up to 12 hours.

To assemble, preheat oven to 350°. Pat vegetable mixture dry with paper towels. Set aside asparagus spears for topping. Add green onions, olive oil, garlic, and remaining ½ tsp. salt and ½ tsp. pepper to vegetable mixture in bowl; toss to combine. Set aside ⅓ cup vegetable mixture for topping.

Spread 1 cup cheese in the partially baked crust. Spread with vegetable mixture from bowl. Sprinkle with pimiento and remaining ¼ cup cheese. Pour egg mixture over top. Cover edges of pastry with foil to prevent overbrowning.

Bake for 45 minutes. Top with reserved vegetable mixture and asparagus spears. Bake for 15 to 20 minutes more or until knife inserted near center comes out clean. Let stand for 30 minutes before serving.