Your translation is correct, and どんな意味が込められているのか考えるもの(=形) is a completely natural Japanese phrase at the same time. Grammatically speaking, I think this is something called a gapless relative clause explained here. Other similar examples include:

• 英語を学ぶ楽しみ the joy of learning English (not "the joy which is learning English")
• カエルが水に飛び込む音 the sound of a frog jumping into water
• よく笑う性格 jovial character
• 彼が考えた結果 the result of his thoughts / his conclusion

Also related: Does 考えさせられる小説 make sense?

Your translation is correct, and どんな意味が込められているのか考えるもの(=形) is a completely natural Japanese phrase at the same time. Grammatically speaking, I think this is something called a gapless relative clause explained here. Other similar examples include:

• 英語を学ぶ楽しみ the joy of learning English (not "the joy which is learning English")
• カエルが水に飛び込む音 the sound of a frog jumping into water
• よく笑う性格 jovial character
• 彼が考えた結果 the result of his thoughts / his conclusion

Also related: Does 考えさせられる小説 make sense?

EDIT: As pointed by broccoli forest, this may not be a gap-less clause because 込める can take に (e.g., 星の形に意味を込める "to put a meaning in the star shape").

Your translation is correct, and どんな意味が込められているのか考える和菓子 is a completely natural Japanese phrase at the same time. It's so natural and straightforward to native Japanese speakers that it may be difficult for them to notice why it's tricky to learners. Grammatically speaking, I think this is something called a gapless relative clause explained here. Other similar examples include:

• 英語を学ぶ楽しみ the joy of learning English (not "the joy which is learning English")
• カエルが水に飛び込む音 the sound of a frog jumping into water
• よく笑う性格 jovial character
• 彼が考えた結果 the result of his thoughts / his conclusion

Your translation is correct, and どんな意味が込められているのか考えるもの(=形) is a completely natural Japanese phrase at the same time. Grammatically speaking, I think this is something called a gapless relative clause explained here. Other similar examples include:

• 英語を学ぶ楽しみ the joy of learning English (not "the joy which is learning English")
• カエルが水に飛び込む音 the sound of a frog jumping into water
• よく笑う性格 jovial character
• 彼が考えた結果 the result of his thoughts / his conclusion

Also related: Does 考えさせられる小説 make sense?