Sesame Peach Crisp

We were visiting friends who cook in the Tetons, and while the views were obscured by the northern California fires, the company and the food were exceptional.
It is funny how you can just click with people, and for me, a common love of cooking is a very good start.
Our last dinner was a joint effort, and our hostess made this exceptional peach crisp from the cover of Bon Appetit.  I cannot emphasize enough how great the sesame flavor married with the peaches.  So so good!
As a side note, I think this would do well with GF flour as well.

• 2½ lb. peaches (6–7)
• 1 lemon
• ⅓ cup plus 1¼ cups sugar
• 1¾ tsp. kosher salt, divided
• ⅓ cup raw white sesame seeds
• 1 cup all-purpose flour
• ½ cup (1 stick) unsalted butter
• ½ tsp. ground cinnamon
• ⅓ cup tahini
• 2 tsp. toasted sesame oil
•  1 tsp. (or more) cornstarch (optional)

Place a rack in top third of oven; preheat to 375°. Now prep your peaches. 
Slice 2½ lb. peaches (6–7) in half with a chef’s knife. Using a paring knife, slice the peaches.   As you go, transfer peach slices to a 13x9" baking dish.
Zest 1 lemon into a medium bowl; set aside.
Sprinkle ⅓ cup sugar, 1 Tbsp. fresh lemon juice (from the zested lemon), and ¾ tsp. salt over peaches. Toss to gently combine, then let sit while you prep the topping—aim for about 20 minutes.  
Spread ⅓ cup raw white sesame seeds on a rimmed baking sheet or in an ovenproof skillet. Toast, tossing halfway through, until golden brown all over, 12–15 minutes.  Immediately transfer to a large bowl (so they don’t keep cooking on hot baking sheet).
Add 1 cup all-purpose flour and remaining 1¼ cups sugar and 1 tsp. salt to bowl with seeds. Whisk to combine.
Add ½ cup (1 stick) butter and ½ tsp. ground cinnamon to medium bowl with lemon zest. Microwave until butter is melted, about 1 minute. Add ⅓ cup tahini and 2 tsp. toasted sesame oil and whisk to combine.
Pour tahini-butter mixture into dry ingredients, then mix until dry ingredients are incorporated and mixture holds together when you squeeze it in your hands
Assemble! The peaches should look juicy. And now you determine whether you’re using 1 tsp. (or more) cornstarch. If peaches are not-so-ripe, skip it entirely. If they’re perfectly ripe, use 1 tsp. And if they’re really juicy, use 2 tsp. Gently toss to combine.
Using your hands, squeeze crumble topping into big hunks, then break off uneven pieces and scatter over peaches.
Bake crumble until topping is well browned and firm and peaches are tender with bubbling juices, 50–70 minutes.