Add vegan butter and sugar to a mixing bowl. Cream them together by beating them with a spoon until well combined.
Add the oat milk and vanilla extract and stir in briefly.
Add flour and baking powder and combine into a uniform, moist dough.
Finally, stir in the oats and chocolate chips to evenly distribute them. The cookie dough will be soft and sticky.
Using two spoons or a cookie scoop, place scoops of dough about two tablespoons in size onto a lined baking sheet. Space them out to allow the cookies to spread. You should fit about 9 cookies per sheet.
Bake at 180°C for 12 - 15 minutes until golden brown.
Leave the cookies on the sheet to firm up for about 5 before moving them onto a wire cooling rack. Wait until the cookies completely cooled down before storing in an airtight container.
For step by step pictures, variations and tips on choosing your ingredients, see the post above.