Access the associative model in Many-To-Many with NestJS Sequelize

First, here is a sort of Diagram of my database and my shared DTOs

The issue is that, when I want to map my Recipe to a RecipeDTO, I can't get the quantity field.

recipe.repository.ts

@Injectable()
export class RecipeRepository {
    public async getAll(): Promise<Recipe[]> {
        return Recipe.findAll({
            include: [Item]
        });
    }

    public async create(recipe: Recipe) {
        try {
            await Recipe.create(recipe);
            return true;
        } catch(err) {
            console.log(err);
            return false;
        }
    }
}

recipe.model.ts

@Table({tableName: 'RECIPE'})
export class Recipe extends BaseModel<Recipe> {
    @Column({field: 'NAME'})
    name: string

    @Column({field: 'IMAGE'})
    image: string

    @BelongsToMany(() => Item, () => ItemRecipe)
    items: Item[]
}

item.model.ts

@Table({tableName: 'ITEM'})
export class Item extends BaseModel<Item> {
    @Column({field: 'NAME'})
    name: string

    @Column({field: 'IMAGE'})
    image: string

    @BelongsToMany(() => Recipe, () => ItemRecipe)
    recipes: Recipe[]
}

item-recipe.model.ts

@Table({tableName: 'ITEM_RECIPE'})
export class ItemRecipe extends BaseModel<ItemRecipe> {

    @Column({field: 'QUANTITY'})
    quantity: number

    @ForeignKey(() => Item)
    @Column({field: 'ITEM_ID'})
    itemId: number

    @ForeignKey(() => Recipe)
    @Column({field: 'RECIPE_ID'})
    recipeId: number
}

recipe.mapper.ts

@Injectable()
export class RecipeMapper {
    constructor(private itemMapper: ItemMapper) {}
    toDto(recipe: Recipe): RecipeDto {
        return {
            name: recipe.name,
            image: recipe.image,
            itemRecipe: recipe.items.map(item => {
                return {
                    item: this.itemMapper.toDto(item),
                    quantity: item.itemRecipe.quantity   <--------- itemRecipe DOES NOT EXISTS
                } as ItemRecipeDto
            })
        } as RecipeDto
    }
}

Finaly, here is an example of JSON that I currently get when I'm not using my mapper (so the returned object is Recipe and not RecipeDTO, and we can see that the ItemRecipe is under each Item):

[
    {
        "id": 1,
        "createdAt": "2021-10-31T19:26:26.507Z",
        "updatedAt": "2021-10-31T19:26:26.507Z",
        "name": "Bouillon de Chair",
        "image": "69741.png",
        "items": [
            {
                "id": 1,
                "createdAt": "2021-10-31T19:26:26.507Z",
                "updatedAt": "2021-10-31T19:26:26.507Z",
                "name": "Viande Intangible",
                "image": "63407.png",
                "ItemRecipe": {
                    "id": 1,
                    "createdAt": "2021-10-31T19:26:26.507Z",
                    "updatedAt": "2021-10-31T19:26:26.507Z",
                    "quantity": 1,
                    "itemId": 1,
                    "recipeId": 1
                }
            }
        ]
    },
    {
        "id": 2,
        "createdAt": "2021-10-31T19:26:26.507Z",
        "updatedAt": "2021-10-31T19:26:26.507Z",
        "name": "Boulette de Viande",
        "image": "69750.png",
        "items": [
            {
                "id": 2,
                "createdAt": "2021-10-31T19:26:53.832Z",
                "updatedAt": "2021-10-31T19:26:53.832Z",
                "name": "Viande Hachée",
                "image": "175008.png",
                "ItemRecipe": {
                    "id": 2,
                    "createdAt": "2021-10-31T19:26:26.507Z",
                    "updatedAt": "2021-10-31T19:26:26.507Z",
                    "quantity": 1,
                    "itemId": 2,
                    "recipeId": 2
                }
            }
        ]
    },
    {
        "id": 3,
        "createdAt": "2021-10-31T19:26:26.507Z",
        "updatedAt": "2021-10-31T19:26:26.507Z",
        "name": "Beignet Astrubien",
        "image": "69115.png",
        "items": [
            {
                "id": 3,
                "createdAt": "2021-10-31T19:27:27.044Z",
                "updatedAt": "2021-10-31T19:27:27.044Z",
                "name": "Viande Faisandée",
                "image": "63348.png",
                "ItemRecipe": {
                    "id": 3,
                    "createdAt": "2021-10-31T19:26:26.507Z",
                    "updatedAt": "2021-10-31T19:26:26.507Z",
                    "quantity": 1,
                    "itemId": 3,
                    "recipeId": 3
                }
            },
            {
                "id": 21,
                "createdAt": "2021-10-31T20:32:03.815Z",
                "updatedAt": "2021-10-31T20:32:03.815Z",
                "name": "Blé",
                "image": "34009.png",
                "ItemRecipe": {
                    "id": 4,
                    "createdAt": "2021-10-31T19:26:26.507Z",
                    "updatedAt": "2021-10-31T19:26:26.507Z",
                    "quantity": 1,
                    "itemId": 21,
                    "recipeId": 3
                }
            }
        ]
    }
]

So in this Many-to-Many association, how can I access the associative model from my Recipe model ?