Mit forslag er, at vi køber varme boller hos bageren og tager dem med til parken.

Because forslag is a neuter noun in Danish: et forslag.

The possessive pronoun my changes form in Danish:

• min for common-gender singular nouns
• mit for neuter singular nouns
• mine for plural nouns

So:

• min bil = my car
• mit forslag = my suggestion
• mine bøger = my books

In this sentence, at introduces a subordinate clause: at vi køber ...

Many Danish writers use a comma before a subordinate clause. That is what you see here:

• Mit forslag er, at vi køber ...

You may also see:

• Mit forslag er at vi køber ...

Both are possible depending on the comma system being used. So the comma here is about punctuation style, not meaning.

Because at starts a subordinate clause, and subordinate clauses in Danish normally use subject + verb order.

So:

• at vi køber = that we buy

Compare that with a main clause, where Danish often uses verb-second word order:

• Vi køber varme boller
• I dag køber vi varme boller

But after at, you do not invert the subject and verb:

• at vi køber ✔
• at køber vi ✘

Both structures are possible in Danish, but they are a little different.

• Mit forslag er, at vi køber varme boller ... = My suggestion is that we buy warm rolls ...

• Mit forslag er at købe varme boller ... = My suggestion is to buy warm rolls ...

The version with vi explicitly says who should do it. It often sounds a bit more direct and conversational. The infinitive version is slightly more abstract.

Danish often uses the present tense for future actions when the context already makes the future meaning clear.

So:

• vi køber ... og tager dem med ...

can mean we buy ... and take them along ... as part of a suggestion about what to do next.

English does something similar in some contexts, but Danish uses this very naturally for plans, arrangements, and suggestions.

If you wanted a different nuance, you could also say things like:

• vi skal købe ... = we will / are going to buy ...
• vi kan købe ... = we can buy ...

But the plain present tense is very normal here.

Because the two verbs share the same subject.

• vi køber ... og tager ...

means:

• we buy ... and take ...

Danish, like English, usually does not repeat the subject when two coordinated verbs have the same subject.

You could repeat it, but it would usually sound heavier or more emphatic:

• ... at vi køber varme boller, og at vi tager dem med til parken

That version is grammatical, but less natural in this simple sentence.

Hos is often used when talking about being at someone's place, with someone, or at a business connected to a person/profession.

So:

• hos bageren = at the baker's / from the bakery

This is very natural in Danish when talking about buying something from a person or shop identified by the profession.

Some useful contrasts:

• hos bageren = at the baker's / from the baker
• fra bageren = from the baker/bakery
• i bageriet = in the bakery

In this sentence, hos bageren sounds very natural for buying rolls.

Because Danish usually marks the definite form by adding an ending to the noun.

So:

• en bager = a baker

• bageren = the baker

• en park = a park
• parken = the park

Unlike English, Danish often does not use a separate word like the by itself. Instead, the noun gets a definite ending.

Because the adjective must agree with the noun.

Here, boller is plural, so the adjective takes -e:

• varme boller = warm rolls

Compare:

• varm bolle = warm roll
• varmt brød = warm bread
• varme boller = warm rolls

So varme is the correct plural form here.

In this context, boller means bread rolls or buns, especially the kind you might buy fresh from a bakery.

The word can cover different kinds of small bread-like baked items, so the exact English word depends on context. Here, because of varme and hos bageren, it most naturally means warm rolls.

Because dem is the object form of the pronoun, while de is the subject form in standard written Danish.

Here, the pronoun refers back to boller, and it is the object of tager:

• tager dem med = take them along

So:

• de = they
• dem = them

In spoken Danish, people do not always keep this distinction clearly, but in standard writing it matters.

Tage ... med is a common Danish expression meaning take ... along or bring ... with you.

So:

• tager dem med til parken = take them along to the park

The word med is part of the expression, but in a normal finite clause it is often separated from the verb:

• tage noget med
• vi tager dem med
• hun tog sin ven med

This is similar to a separable verb or a phrasal-style expression.

Because til shows direction or destination, while i shows location.

• til parken = to the park
• i parken = in the park

So in this sentence:

• tager dem med til parken means you are bringing them to the park.

If you were describing where you are already doing something, you would use i:

• Vi spiser dem i parken = We eat them in the park.