Le dessus de la tarte est couvert de framboises.

Le dessus means the top or the upper side/surface of something.

So le dessus de la tarte is the top of the pie/tart.

A useful point: dessus can be used in different ways in French.

• le dessus = a noun, the top
• dessus by itself can also act more like on top / above / on it, depending on context

In this sentence, it is clearly a noun because it has the article le before it.

French often uses le dessus de... very naturally to talk about the top surface of something.

So:

• le dessus de la tarte = the top of the tart
• le dessus de la table = the top of the table

A learner might think of haut, but le haut usually means the upper part in a more general sense, not specifically the exposed top surface. For a tart, le dessus is the most natural choice.

Because tarte is a feminine noun.

So the singular definite article is:

• masculine: du = de + le
• feminine: de la
• before vowel sound: de l'

Since it is la tarte, you get:

• le dessus de la tarte

If the noun were masculine, you would have:

• le dessus du gâteau = the top of the cake

Because couvert agrees with le dessus, not with la tarte.

The subject of the sentence is:

• Le dessus de la tarte

The main noun in that subject is dessus, which is masculine singular. So the adjective/past participle must also be masculine singular:

• est couvert

Even though tarte is feminine, it is inside the de... phrase and is not the word controlling the agreement.

Compare:

• Le dessus de la tarte est couvert → dessus is masculine
• La tarte est couverte → tarte is feminine

This is a very common thing for English speakers to watch out for.

After couvert, French normally uses de to say what something is covered with.

So:

• couvert de sucre = covered with sugar
• couvert de neige = covered with snow
• couvert de framboises = covered with raspberries

This is just the standard pattern: être couvert de + thing.

Using des framboises here would sound wrong in normal French. After expressions like couvert de, rempli de, garni de, French often uses plain de, even when English would use with plus a plural noun.

Yes, in this sentence it does.

• être couvert de = to be covered with

So est couvert de framboises means is covered with raspberries.

French uses de where English uses with. That is very common, so it is best to learn the whole expression as a chunk:

• être couvert de
• être rempli de
• être entouré de

Yes, absolutely.

• La tarte est couverte de framboises = The tart is covered with raspberries.

The difference is mainly one of focus:

• Le dessus de la tarte est couvert de framboises focuses specifically on the top
• La tarte est couverte de framboises sounds broader and may suggest the tart as a whole is covered, or simply that raspberries are all over it

So the original sentence is more precise.

It is historically the past participle of couvrir (to cover), but in sentences like this it functions very much like an adjective.

So in practice, you can think of:

• est couvert de framboises = is covered with raspberries

Just remember that it agrees in gender and number like an adjective:

• Le dessus est couvert
• La tarte est couverte
• Les gâteaux sont couverts

The structure is:

• Le dessus de la tarte = subject
• est = verb (is)
• couvert de framboises = description of the subject

So it breaks down like this:

• Le dessus = the top
• de la tarte = of the tart
• est = is
• couvert de framboises = covered with raspberries

This is a very standard French pattern:

[subject] + être + adjective/past participle + de + noun

Here framboises is used in a general material/content sense: the top is covered with raspberries.

French often leaves out the article after expressions like couvert de when the noun refers to what something is filled, covered, or decorated with.

So this does not mean the specific raspberries in the sense of the raspberries we already mentioned. It just means raspberries as the topping.

A few pronunciation notes:

• Le dessus: the final -s in dessus is usually silent
• tarte: one syllable, with a clear French r
• framboises: the -s at the end is silent

Also note the rhythm:

• Le dessus de la tarte est couvert de framboises

In careful speech, est may be very light, and the whole sentence flows quite smoothly. A learner should especially notice that many final consonants are not pronounced.