Fetching details from the dictionary...

serving (of food); helping
chilled soba served on a dish (often on a wicker basket or in a shallow steaming basket) with dipping sauce
「盛り」 has another reading with different meanings.
このラーメンは大盛りで注文しよう。
Let's order this ramen in a large serving.
ご飯の盛りがとても豪華に見えた。
The serving of rice looked very luxurious.
彼女は料理の盛りつけが上手だ。
She is good at arranging food servings.