It is a celebration and formal announcement of your intentions and so there are speeches (as many or as few as you like) and like all celebrations, you can have a cake.
It can be as simple as a small gathering or a huge formal affair.
Traditionally the bride’s parents would host the party, the Groom’s parents are the next option, but commonly this has changed to parents of both the Bride & Groom contributing, or even the couple themselves; so really anyone can host it.
The ‘host’ is the one who organises and finances.
On rare occasions, it is the bridal party (Maid of Honour) who hosts the show, but as the Bridal Party may not yet be confirmed and the Maid of Honour, will be in charge of others gatherings later, it is probably for others to manage the Engagement party.
The Engagement Party would usually be held within 3 months of the actual proposal and some months (at least 6) before the wedding, so the Engagement party should be closer to the proposal than it is to the wedding day.
It is entirely a matter of choice and practicality as to whether you have one but an engagement party announces your love to the world and your intention to marry.
An engagement party is also an opportunity to invite guests that might not attend the wedding.
You can even have your Celebrant attend for a commitment ceremony and ring blessing.
With thanks! Valuable information!