Toast the oats: Preheat oven to 350°F (175°C). Spread the rolled oats on a baking sheet and toast for 6–8 minutes, stirring once halfway, until they smell nutty and are just golden. Why: Toasting intensifies the oat flavor and reduces excess surface moisture so the cookies hold their shape and have a clean oat taste.

Prepare the cornstarch binder (egg-free 'slurry'): Whisk 1 tablespoon cornstarch with 3 tablespoons warm water until smooth and glossy. Let sit 2 minutes to thicken. Why: Cornstarch heated/rehydrated provides viscous, egg-white-like binding power; it helps the cookie set and gives chewiness without eggs.

Cream butter and sugars: In a large bowl, beat the softened butter, brown sugar and honey until pale, smooth and slightly fluffy (about 2–3 minutes). Add the vegetable oil and molasses and beat to combine. Why: Creaming incorporates air for lightness and dissolves the sugar into the fat for an even texture; adding oil and molasses adds chewiness and depth.

Add wet flavorings: Mix in the cornstarch slurry, powdered milk, lemon juice and lemon zest until evenly distributed. Why: Powdered milk adds structure and a rounded dairy note that mimics the richness of eggs; lemon components brighten the overall flavor and interact with the baking soda to create subtle lift.

Combine dry ingredients: In a separate bowl whisk together the toasted oats, flour, baking soda, baking powder, ground ginger and salt so the leaveners and spice are evenly dispersed. Why: Sifting or whisking dry ingredients prevents pockets of baking soda/powder and ensures uniform rise and flavor throughout the batch.

Fold wet into dry: Add the dry mixture to the wet mixture and fold gently with a flexible spatula until just combined — stopping when no streaks of flour remain. Overmixing develops gluten in the flour and will make the cookies tough; gentle folding preserves tenderness and chew.

Chill the dough: Transfer the dough to the refrigerator for 30 minutes (or up to 2 hours). Why: Chilling firms the butter and solidifies the oil-coated matrix so the cookies spread less and develop a chewier interior with crisp edges when baked.

Portion the cookies: Line baking sheets with parchment. Scoop dough into 2-tablespoon mounds (about 24 mounds) and arrange 2 inches apart. Lightly press each mound to flatten slightly (these cookies don’t spread hugely because they contain oats). If you like, sprinkle a pinch of granulated sugar on top for sparkle. Why: Uniform scoops ensure even baking; a slight flatten prevents tops from staying domed while the centers bake.

Bake: Bake at 350°F (175°C) for 12–14 minutes, rotating the pan once at the halfway mark. The edges should be golden and the centers set but slightly soft. Why: Moderate oven temperature allows the sugars to caramelize for flavor while baking the oats through without drying the cookie out.

Cool properly: Remove from oven and let cookies rest on the baking sheet for 5 minutes; they will finish setting as they cool. Transfer to a wire rack to cool completely. Why: Cooling on the sheet lets residual heat finish cooking the centers without overbrowning; a wire rack prevents sogginess from trapped steam.

Storage: Store cooled cookies in an airtight container at room temperature for up to 4 days, or freeze for up to 3 months. For best texture after refrigeration or freezing, warm gently in a 300°F (150°C) oven for 5 minutes to revive chewiness. Why: Proper storage preserves the crisp edge/chewy center contrast.