Grocery shopping is one of the few expenses we can't skip. According to WalletHub, the average monthly grocery bill for two people is about $557. That adds up to nearly $6,700 a year.

Now imagine earning 6% cash back on most of that spend. With the Blue Cash Preferred® Card from American Express, you can do exactly that -- on up to $6,000 in annual U.S. supermarket purchases. (American Express is a Motley Fool Money advertiser.)

That's a potential $360 back every year, just for buying your normal groceries. Here are all the card deets:

Earn 6% cash back on groceries

This is one of the best cards for grocery rewards available today. You'll earn 6% cash back at U.S. supermarkets (up to $6,000 per year in purchases) and select U.S. streaming subscriptions. Terms apply. That cap resets every calendar year.

So if you're spending around the national average of $557/month, you'd hit the $6,000 cap in under 11 months. That unlocks the maximum $360 in annual grocery rewards.

Here's a quick chart showing potential cash back at different monthly spending amounts:

Important: Purchases at Target, Walmart, and other superstores don't count toward the 6% grocery category. So beware if you do all your grocery shopping at these places!

For my household (two adults, two kids), we are starting to pass $1,000 per month in grocery spend. But even for single spenders, it's not too hard to spend $100 at the grocery store each week, which would mean about $300 in cash back a year.

If you don't have a good rewards card for groceries right now, it's time to get one. Apply today and start earning up to 6% cash back today with the Amex Blue Cash Preferred.

Extra perks beyond groceries

Groceries are just the beginning of cash back opportunities. Here's the full lineup of earning opportunities for the Amex Blue Cash Preferred:

• 6% cash back on U.S. supermarkets (up to $6,000 per year in purchases) and select U.S. streaming subscriptions
• 3% cash back on U.S. gas stations and transit (including taxis/rideshare, parking, tolls, trains, buses and more)
• 1% cash back on other purchases
• Terms apply

Gas station cash back can be a pretty major perk for all you road warriors out there. When my wife and I drive to Montana each summer, we drop about $600 on gas for the trip. This would earn us about $18 back -- enough to pay for five Redbulls to keep us awake at the wheel.

The Amex Blue Cash Preferred has a $0 intro annual fee for the first year, then $95. (See rates and fees.) But if you max out the grocery cash back alone, you're coming out well ahead.

A sweet $250 welcome offer, too!

Right now, the Amex Blue Cash Preferred includes a $250 welcome offer after you spend $3,000 on purchases in the first 6 months. Terms apply.

It's worth noting that card welcome offers like this can change at any time with short notice. So if you've been waiting for a good reason to upgrade your grocery rewards game, this is probably it.

Is this card right for you?

The Amex Blue Cash Preferred is a great fit if you spend a lot on groceries and streaming services.

It's especially valuable for families that can easily hit the $6,000 annual grocery cap, plus have a higher than usual spend at gas stations. Just be sure to pay your balance in full each month to avoid interest charges.

Apply for the Blue Cash Preferred® Card from American Express today and start earning up to $360/year on groceries. And score that welcome bonus while you're at it!