Sure! Here are the best-fit options for each blank in the advertisement:

1. **A. learn** - "Want to impress your friends and family with delicious home-cooked meals? Our online cooking classes (1) learn you how to prepare gourmet dishes..."

2. **D. discover** - "...with step-by-step video tutorials and expert tips, you’ll (2) discover the skills you need..."

3. **C. teach** - "You can learn at your own pace and (3) learn new techniques that will take your cooking to the next level."

4. **A. improve** - "Don’t miss the chance to (4) improve your culinary skills..."

5. **D. access** - "...sign up now and (5) access to our exclusive recipe collection."

6. **C. the simplest** - "Cooking has never been (6) the simplest..."

So the filled blanks would be:
1 - A, 2 - D, 3 - C, 4 - A, 5 - D, 6 - C.