Prep your pan. Line a large baking sheet with parchment paper or a silicone mat. Preheat the oven to 350°F (175°C).

Mix dry ingredients. In a medium bowl, whisk almond flour, coconut flour, gelatin, baking powder, and salt until evenly combined and lump-free.

Whisk wet ingredients. In a large bowl, whisk the melted butter, brown-style sweetener, and allulose until the mixture looks glossy and slightly thick, about 30–45 seconds. Add the egg, egg yolk, vanilla, and vinegar. Whisk until smooth.

Combine dough. Add dry ingredients to the wet bowl and fold with a spatula until just combined. The dough will seem soft; it should not be greasy or runny. Fold in chocolate chips (and nuts if using).

Chill briefly. Cover and chill the dough for 20–30 minutes. This prevents over-spreading and builds that soft-center/crisp-edge contrast.

Shape giant cookies. Scoop 1/4 cup portions (about 70 g each). Roll into balls, then gently flatten to about 3/4 inch thick on the tray, spacing 3 inches apart. You should get 8–10 giant cookies.

Bake. Bake 10–13 minutes until the edges are set and lightly golden, but the centers still look slightly soft and puffed. Do not overbake—carryover heat will finish them.

Finish and cool. If desired, press a few extra chocolate chips on top and sprinkle with flaky salt. Cool on the tray for 10 minutes before transferring to a rack. They firm up as they cool.

Enjoy. Eat warm for a gooey center, or let cool fully for chewier centers with crisper edges.