Ingredients:
1 small butternut squash, halved and seeded
Neutral oil, such as vegetable or grapeseed
Breast milk, formula, or filtered water, as needed
1 (10-ounce) bag frozen spinach
2 medium apples, peeled, cored, and cut into 1-inch chunks
Directions:
Prep the butternut squash purée: Heat the oven to 400°F. Rub the squash all over with oil, then place on a sheet pan, cut side down. Roast for about 45 minutes, until the flesh is tender. Use a spoon to scoop out the flesh and transfer it to a blender or food processor. Add ⅓ to ½ cup of breast milk, formula, or filtered water. Purée to the desired consistency, adding more liquid to thin as needed.
Prep the spinach purée: Cook the spinach according to the package instructions. Let cool, then squeeze out any excess liquid (either discard or reserve for blending). Transfer the spinach to a blender or food processor. Add ⅓ to ½ cup of spinach liquid, breast milk, formula, or filtered water. Purée to the desired consistency, adding more liquid to thin as needed.
Prep the apple purée: Bring ½ cup of filtered water to a simmer in a medium saucepan, add the fruit, and simmer until fork-tender, 5 to 10 minutes. Let cool in the pan, then transfer the fruit and liquid to a blender or food processor and purée until smooth, adding more filtered water (or breast milk or formula) as needed to adjust the consistency.
Portion and freeze the purées: Spoon or pour the purées into clean ice cube trays or baby food trays. Freeze until solid. Transfer the cubes to a freezer bag, label and date them—purées will stay good in the freezer for up to 3 months—and stash in the freezer.
Thaw before mealtime: Thaw the purées overnight in the refrigerator or, in a pinch, zap in the microwave.
Ready, set, eat: Combine 1 thawed cube each of butternut purée, apple purée, and spinach purée. Gently heat until warm.