Oven temperature tips! Baking at 350F was a bit too low; the cookies spread. Baking at 375F was a bit too high; the exterior took on too much color before the interior was fully baked. I found 365F just about right. I bake at a higher elevation (about 5000 feet), so I tend to bake at a slightly higher temperature. Depending on your oven, the temp may work best between 360 and 370F.
See the blog post for more details on why cream of tartar and cornstarch are included with the dry ingredients for this recipe. The cookies will bake and puff, keeping their shape pretty well. After scooping the batter (2 tablespoons, about golf ball sized, 50 grams), you'll want to roll the cookie batter to smooth the edges, then slightly press it very gently on the cookie sheet. Avoid pressing it too much, or the cookies will flatten with baking.
With baking, the cookies will rise, puff a bit, then crack in some places (on the surface). Take them out once the bottoms appear slightly golden but no color on the tops - about 9 to 10 minutes at 365F. As they cool, they'll settle a tiny bit but should hold their shape overall.