Please choose the correct ending to complete the given sentence: Food and Entertaining: [header] How to make jello cookies [title] Preheat the oven to 350 ° f (180 ° c) and line a baking sheet with parchment paper or grease. [title] Combine the butter, sugar, gelatin, eggs and vanilla in a mixing bowl and beat the ingredients on medium speed using a spatula, a handheld mixer or a stand mixer with a paddle attachment. [title] Whisk together the flour, baking powder and salt in a separate mixing bowl.

Ending1: [title] Whisk together the egg and milk in a separate bowl. [title] Pour in the gelatin liquid into the flour. Ending2: [title] Add the vanilla and egg mixture to the butter mixture. [title] Beat the two together in a separate bowl. Ending3: [title] Add 1/2 cup of the dry ingredients to the wet ingredients while mixing at medium speed. [step] You can also hand-mix if preferred. Ending4: [title] Transfer the mixture to the greased baking sheet. [title] Bake the cake for 5 minutes at 350 ° f (177 ° c).

Answer format: ending1/ending2/ending3/ending4