1-Preheat oven: Preheat oven to 350°F (177°C) and line a baking pan with parchment paper, leaving an overhang for easy removal just like flipping a page in your favorite cookbook.

2-In a large bowl: beat the softened butter, granulated sugar, and brown sugar on medium-high speed until they’re fluffy and light, which takes about 3 minutes; then beat in the eggs and vanilla, scraping the bowl as you go to mix everything evenly.

3-In another bowl: whisk together the 2 and 1/3 cups (291g) all-purpose flour, baking powder, cream of tartar, and salt; add this to your wet mix and beat on low until just combined, then stir in 1 cup (180g) white chocolate morsels the dough will be thick and sticky, but that’s what makes it great.

4-Spoon half the dough: into the prepared pan and press it into an even layer using generously floured hands to keep things from sticking.

5-Mix the 1/4 cup: (50g) granulated sugar and 2 teaspoons ground cinnamon for the filling, then sprinkle about 3/4 of it over the bottom dough layer, saving the rest for later.

6-Flatten small handfuls: of the remaining dough between your floured hands and lay them over the cinnamon sugar, overlapping a bit like roof shingles it’s okay if some cinnamon peeks through.

7-Press the reserved 1 tablespoon: of white chocolate morsels into the top dough and sprinkle on the rest of the cinnamon sugar mixture for that extra crunch.

8-Bake for 32 to 35 minutes: until golden brown; check with a toothpick it should come out with moist crumbs to avoid overbaking.

9-Cool the bars: completely in the pan on a wire rack, which takes about 1 hour, so patience pays off here.

10-Using the parchment overhang: lift the bars out and cut them into squares for serving.