To get all browser cookies, use the cy.getCookies() command.
cy
.getCookies().should("not.have.property", "fakeCookie1")
.get(".get-cookies-btn").click()
.getCookies().should("have.property", "fakeCookie1", "123ABC")
To clear all browser cookies, use the cy.clearCookies() command.
cy
.getCookies().should("not.have.property", "fakeCookie1")
.get(".clear-cookies-btn").click()
.getCookies().should("have.property", "fakeCookie1", "123ABC")
// clearCookies() returns cookie represented as an object
.clearCookies().should("not.have.property", "fakeCookie1")