Serving size of 1cup (180g) spinach (cooked) has 0.425 mg vitamin B2, which is 26% of the RDA for lactating women.
Serving of 1cup (180g) of spinach is also a good source of other priority 1 nutrients for lactating women, such as Vitamin E, vitamin B6, and pro-vitamin A (RAE).
Find a recipe with Spinach here